Keep the current interface but ignore the KM_type and use a stack based
approach.

The advantage is that we get rid of crappy code like:

	#define __KM_PTE			\
		(in_nmi() ? KM_NMI_PTE : 	\
		 in_irq() ? KM_IRQ_PTE :	\
		 KM_PTE0)

and in general can stop worrying about what context we're in and what kmap
slots might be appropriate for that.

The downside is that FRV kmap_atomic() gets more expensive.

For now we use a CPP trick suggested by Andrew:

  #define kmap_atomic(page, args...) __kmap_atomic(page)

to avoid having to touch all kmap_atomic() users in a single patch.

[ not compiled on:
  - mn10300: the arch doesn't actually build with highmem to begin with ]

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix up drivers/gpu/drm/i915/intel_overlay.c]
Acked-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NChris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.

New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time.  Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.

The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.

Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.

Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.

===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
//   but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}

@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}

@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
   *off = E
|
   *off += E
|
   func(..., off, ...)
|
   E = *off
)
...+>
}

@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}

@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
  *off = E
|
  *off += E
|
  func(..., off, ...)
|
  E = *off
)
...+>
}

@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}

@ fops0 @
identifier fops;
@@
struct file_operations fops = {
 ...
};

@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
 .llseek = llseek_f,
...
};

@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
 .read = read_f,
...
};

@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
 .write = write_f,
...
};

@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
 .open = open_f,
...
};

// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
...  .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};

@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
...  .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};

// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
...  .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};

// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};

// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};

@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+	.llseek = default_llseek, /* write accesses f_pos */
};

// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////

@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
 .write = write_f,
 .read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};

@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};

@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};

@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>

The i915 driver has quite a few module unload bugs, the known ones at
least have fixes that are targeting 2.6.37. However, in order to
maintain a stable kernel, we should prevent this known random memory
corruption following driver unload. This should have very low impact on
normal users who are unlikely to need to unload the i915 driver.
Suggested-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@kernel.org
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

since the handle references are all tied to a file_priv, and when it disappears
all the handle refs go with it.

The fbcon ones we'd only notice on unload, but the nouveau notifier one
would would happen on reboot.

nouveau: Reported-by: Marc Dionne <marc.c.dionne@gmail.com>
nouveau: Tested-by: Marc Dionne <marc.c.dionne@gmail.com>
i915 unload: Reported-by: Keith Packard <keithp@keithp.com>
Acked-by: NBen Skeggs <bskeggs@redhat.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

... and do the same for pread.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

Move the access control up from the fast paths, which are no longer
universally taken first, up into the caller. This then duplicates some
sanity checking along the slow paths, but is much simpler.
Tracked as CVE-2010-2962.
Reported-by: NKees Cook <kees@ubuntu.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

Instead of waiting for the display line value to settle, we can simply
wait for the pipe configuration register 'state' bit to turn off.

Contrarywise, disabling the plane will not cause the display line
value to stop changing, so instead we wait for the vblank interrupt
bit to get set. And, we only do this when we're not about to wait for
the pipe to turn off.
Signed-off-by: NKeith Packard <keithp@keithp.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

While the display port is in training mode, vblank interrupts don't
occur. Because we have to wait for the display port output to turn on
before starting the training sequence, enable the output in 'normal'
mode so that we can tell when a vblank has occurred, then start the
training sequence.
Signed-off-by: NKeith Packard <keithp@keithp.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

Extend the error handling code with operations found in other nearby error
handling code

A simplified version of the sematic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@r exists@
@r@
statement S1,S2,S3;
constant C1,C2,C3;
@@

*if (...)
 {... S1 return -C1;}
...
*if (...)
 {... when != S1
    return -C2;}
...
*if (...)
 {... S1 return -C3;}
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

Now that we hold onto a reference whilst evicting objects, we need to
be sure that we drop all the references taken -- even on the error
paths.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

There were lots of places being inconsistent since handle count
looked like a kref but it really wasn't.

Fix this my just making handle count an atomic on the object,
and have it increase the normal object kref.

Now i915/radeon/nouveau drivers can drop the normal reference on
userspace object creation, and have the handle hold it.

This patch fixes a memory leak or corruption on unload, because
the driver had no way of knowing if a handle had been actually
added for this object, and the fbcon object needed to know this
to clean itself up properly.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDave Airlie <airlied@redhat.com>

The IPS driver needs to know the current power consumption of the GMCH
in order to make decisions about when to increase or decrease the CPU
and/or GPU power envelope.  So fix up the divisions to save the results
so the numbers are actually correct (contrary to some earlier comments
and code, these functions do not modify the first argument and use it
for the result).
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

In the event that the external chipset doesn't implement the
GET_SUPPORTED_ENHANCEMENTS commands, gracefully treat it as having no
enhancments rather than bailing.
Reported-and-tested-by: NWoody Suwalski <terraluna977@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=18342Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

We weren't unlinking the freed connector from the drm lists, and so
hit some use-after-free if we failed to initialise the connector.
Reported-and-tested-by: NWoody Suwalski <terraluna977@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=18342Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

A minor typo caused a single fence register to be incorrectly
programmed, resulting in occassional tiling corruption.
Reported-and-tested-by: NHans de Bruin <bruinjm@xs4all.nl>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=18962Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

During heavy aperture thrashing we may be forced to wait upon several active
objects during eviction. The active list may be the last reference to
these objects and so the action of waiting upon one of them may cause
another to be freed (and itself unbound). To prevent the object
disappearing underneath us, we need to acquire and hold a reference
whilst unbinding.

This should fix the reported page refcount OOPS:

kernel BUG at drivers/gpu/drm/i915/i915_gem.c:1444!
...
RIP: 0010:[<ffffffffa0093026>]  [<ffffffffa0093026>] i915_gem_object_put_pages+0x25/0xf5 [i915]
Call Trace:
 [<ffffffffa009481d>] i915_gem_object_unbind+0xc5/0x1a7 [i915]
 [<ffffffffa0098ab2>] i915_gem_evict_something+0x3bd/0x409 [i915]
 [<ffffffffa0027923>] ? drm_gem_object_lookup+0x27/0x57 [drm]
 [<ffffffffa0093bc3>] i915_gem_object_bind_to_gtt+0x1d3/0x279 [i915]
 [<ffffffffa0095b30>] i915_gem_object_pin+0xa3/0x146 [i915]
 [<ffffffffa0027948>] ? drm_gem_object_lookup+0x4c/0x57 [drm]
 [<ffffffffa00961bc>] i915_gem_do_execbuffer+0x50d/0xe32 [i915]
Reported-by: NShawn Starr <shawn.starr@rogers.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=18902Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

There is a second revision of B43 (a desktop gen4 part) floating around,
functionally equivalent to the original B43, so simply add the new
PCI-IDs.

Bugzilla: https://bugs.freedesktop.org/show_bugs.cgi?id=30221Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

With 5 places to update when adding handling for fence registers, it is
easy to overlook one or two. Correct that oversight, but fence
management should be improved before a new set of registers is added.

Bugzilla: https://bugs.freedesktop.org/show_bug?id=30199
Original patch by: Yuanhan Liu <yuanhan.liu@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

These are not fatal errors, so do not alarm the user by filling the
logs with *** ERROR ***. Especially as we know that g4x CRT detection
is a little sticky.

On the one hand the errors are valid since they are warning us of a
stall -- we poll the register whilst holding the mode lock so not even
the mouse will update. On the other hand, those stalls were already present
yet nobody complained.
Reported-by: NAndi Kleen <andi@firstfloor.org>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=18332Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

The drm device drivers currently allow seeking on the
character device but never care about the actual
file position.

When we change the default llseek operation to be
no_llseek, calling llseek on a drm device would
return an error condition, which is an API change.

Explicitly setting noop_llseek lets us keep the
current API.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org

v2: Julien Cristau pointed out that @nondestructive results in
double-negatives and confusion when trying to interpret the parameter,
so use @force instead. Much easier to type as well. ;-)

And fix the miscompilation of vmgfx reported by Sedat Dilek.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org
Signed-off-by: NDave Airlie <airlied@redhat.com>

Destructive load-detection is very expensive and due to failings
elsewhere can trigger system wide stalls of up to 600ms. A simple
first step to correcting this is not to invoke such an expensive
and destructive load-detection operation automatically.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=29536
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=16265Reported-by: NBruno Prémont <bonbons@linux-vserver.org>
Tested-by: NSitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org
Signed-off-by: NDave Airlie <airlied@redhat.com>

This should fix the mysterious mode setting failures reported during
boot up and after resume, generally for i8xx class machines.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=16478Reported-and-tested-by: NXavier Chantry <chantry.xavier@gmail.com>
Buzilla: https://bugs.freedesktop.org/show_bug.cgi?id=29413Tested-by: NDaniel Vetter <daniel@ffwll.ch>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

We don't know how to enable it safely, especially as outputs turn on and
off.  When disabling LP1 we also need to make sure LP2 and 3 are already
disabled.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=29173
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=29082Reported-by: NChris Lord <chris@linux.intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@kernel.org
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

If we are busy, then we may have woken up the wait_request handler but
not yet serviced it before the hang check fires. So in hang check,
double check that the i915_gem_do_wait_request() is still pending the
wake-up before declaring all hope lost.

Fixes regression with e78d73b1.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=30073Reported-and-tested-by: NSitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

This reverts commit b9421ae8.

This warning was so prelevant, even for apparently working machines,
that it was just causing fear, anxiety and panic.

The root cause still remains, so we will add some better debugging when
we focus on fixing it.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=17021Reported-by: NMaciej Rutecki <maciej.rutecki@gmail.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

This reverts commit 0f3ee801.

Enabling LVDS on pipe A was causing excessive wakeups on otherwise idle
systems due to i915 interrupts. So restrict the LVDS to pipe B once more,
whilst the issue is properly diagnosed.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=16307Reported-and-tested-by: NEnrico Bandiello <enban@postal.uv.es>
Poked-by: NFlorian Mickler <florian@mickler.org>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Adam Jackson <ajax@redhat.com>
Cc: stable@kernel.org

This reverts commit ce171780.

This commit has been independently bisected a few times as being the cause
of a s2ram failure.
Reported-and-tested-by: NKyle McMartin <kyle@mcmartin.ca>
Reported-and-tested-by: NAndy Isaacson <adi@hexapodia.org>
Cc: Zou Nan hai <nanhai.zou@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

New pci ids for GT2 and GT2+ on desktop and mobile sandybridge,
and graphics device ids for server sandybridge. Also rename original
ids string to reflect GT1 version.
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

MI_FLUSH is being deprecated, but still available on Sandybridge.
Make sure it's enabled as userspace still uses MI_FLUSH.
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

Sandybridge GTT has new cache control bits in PTE, which controls
graphics page cache in LLC or LLC/MLC, so we need to extend the mask
function to respect the new bits.

And set cache control to always LLC only by default on Gen6.
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

Arguably this is a bug in drm-core in that we should not be called twice
in succession with DPMS_ON, however this is still occuring and we see
FDI link training failures on the second call leading to the occassional
blank display. For the time being ignore the repeated call.

Original patch by Dave Airlie <airlied@redhat.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

We were passing garbage values into the panel-fitter control register
when disabling it on Ironlake - those values (filter modes and reserved
MBZ bits) would have then be re-used the next time panel-fitting was
enabled.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

When we miss the flip prepare interrupt, we never get into the
software state needed to restart userspace, resulting in a freeze of a
full-screen OpenGL application (such as a compositor).

Work around this by checking DSPxSURF/DSPxBASE to see if the page flip
has actually happened. If it has, do the work we would have done when
the flip prepare interrupt comes in.

Also, add debugfs information to tell us what's going on (based on the
patch from Chris Wilson attached to bugs.fdo bug #29798).
Signed-off-by: NSimon Farnsworth <simon.farnsworth@onelan.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

We reset intel_encoder for every matching encoder whilst iterating over
the encoders attached to this crtc when changing mode. As such in a
cloned configuration intel_encoder may not correspond to the correct
is_edp encoder.

By scoping intel_encoder to the loop, not only is the compiler able to
spot this mistake, we also improve readiability for ourselves.
[It might not be a mistake, within this function it is unclear as to
whether it is permissable for eDP to be cloned...]
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

We were failing when trying to allocate the resource for MMIO of the
MCHBAR because we forgot to specify what type of resource we wanted.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: stable@kernel.org
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>

Only stop trying if the aux channel sucessfully reports that the
transmission was completed, otherwise try again. On the 5th failure,
bail and report that something is amiss.

This fixes a sporadic failure in reading the EDID for my external panel
over DP.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

If the VBIOS tells us the mapping of the SDVO device onto the DDC bus,
use it. However, if there is no VBIOS available that mapping is
uninitialised and we should fallback to our earlier guess.

Fix regression introduced in b1083333 (which in turn is a fix for the
regression caused by the introduction of this guess, 14571b4c).

References:

  Bug 29499 - [945GM] Screen disconnected because of missing VBIOS
  https://bugs.freedesktop.org/show_bug.cgi?id=29499

  Bug 15109 - i945GM fails to detect EDID on DVI port
  https://bugzilla.kernel.org/show_bug.cgi?id=15109Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reported-and-tested-by: NPaul Neumann <paul104x@yahoo.de>
Cc: Adam Jackson <ajax@redhat.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: stable@kernel.org

Adam Hill reported that his Arrandale system required a much longer, up
to 200x500us, wait for the panel to initialise or else modesetting would
fail.

References:

  https://bugs.freedesktop.org/show_bug.cgi?id=29141Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reported-and-tested-by: NAdam Hill <sidepipeuk@yahoo.co.uk>

Lets try to avoid repeating old bugs.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>