Skip to content

R
raspberrypi-kernel

openeuler / raspberrypi-kernel

通知 13
Star 1
Fork 0
R
raspberrypi-kernel
切换分支/标签
  1. 14 5月, 2012 1 次提交
    • H
      [media] v4l2-dev: add flag to have the core lock all file operations · 5126f259
      由 Hans Verkuil 提交于 
      This used to be the default if the lock pointer was set, but now that lock is by
default only used for ioctl serialization. Those drivers that already used
core locking have this flag set explicitly, except for some drivers where
it was obvious that there was no need to serialize any file operations other
than ioctl.

The drivers that didn't need this flag were:

drivers/media/radio/dsbr100.c
drivers/media/radio/radio-isa.c
drivers/media/radio/radio-keene.c
drivers/media/radio/radio-miropcm20.c
drivers/media/radio/radio-mr800.c
drivers/media/radio/radio-tea5764.c
drivers/media/radio/radio-timb.c
drivers/media/video/vivi.c
sound/i2c/other/tea575x-tuner.c

The other drivers that use core locking and where it was not immediately
obvious that this flag wasn't needed were changed so that the flag is set
together with a comment that that driver needs work to avoid having to
set that flag. This will often involve taking the core lock in the fops
themselves.

Eventually this flag should go and it should not be used in new drivers.

There are a few reasons why we want to avoid core locking of non-ioctl
fops: in the case of mmap this can lead to a deadlock in rare situations
since when mmap is called the mmap_sem is held and it is possible for
other parts of the code to take that lock as well (copy_from_user()/copy_to_user()
perform a down_read(&mm->mmap_sem) when a page fault occurs).

It is very unlikely that that happens since the core lock serializes all
fops, but the kernel warns about it if lock validation is turned on.

For poll it is also undesirable to take the core lock as that can introduce
increased latency. The same is true for read/write.

While it was possible to make flags or something to turn on/off taking the
core lock for each file operation, in practice it is much simpler to just
not take it at all except for ioctl and leave it to the driver to take the
lock. There are only a handful fops compared to the zillion ioctls we have.

I also wanted to make it obvious which drivers still take the lock for all
fops, so that's why I chose to have drivers set it explicitly.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>
      5126f259
  3. 11 4月, 2012 1 次提交
  5. 08 3月, 2012 1 次提交
    • G
      [media] em28xx: pre-allocate DVB isoc transfer buffers · 86d38d1e
      由 Gianluca Gennari 提交于 
      On MIPS/ARM set-top-boxes, as well as old x86 PCs, memory allocation failures
in the em28xx driver are common, due to memory fragmentation over time, that
makes impossible to allocate large chunks of coherent memory.
A typical system with 256/512 MB of RAM fails after just 1 day of uptime (see
the old thread for detailed reports and crashlogs).

In fact, the em28xx driver allocates memory for USB isoc transfers at runtime,
as opposite to the dvb-usb drivers that allocates the USB buffers when the
device is initialized, and frees them when the device is disconnected.

Moreover, in digital mode the USB isoc transfer buffers are freed, allocated
and cleared every time the user selects a new channel, wasting time and
resources.

This patch solves both problems by allocating DVB isoc transfer buffers in
em28xx_usb_probe(), and freeing them in em28xx_usb_disconnect().
In fact, the buffers size and number depend only on the max USB packet size
that is parsed from the USB descriptors in em28xx_usb_probe(), so it can
never change for a given device.

This approach makes no sense in analog mode (as the buffer size depends on
the alternate mode selected at runtime), the patch creates two separate sets
of buffers for digital and analog modes.

For digital-only devices, USB buffers are created when the device is probed
and freed when the device is disconnected.
For analog-only devices, nothing changes: isoc buffers are created at runtime.
For hybrid devices, two sets of buffers are maintained: the digital-mode
buffers are created when the device is probed, and freed when the device is
disconnected; analog-mode buffers are created/destroyed at runtime as before.
So, in analog mode, digital and analog buffers coexists at the same time: this
can be justified by the fact that digital mode is by far more commonly used
nowadays, so it makes sense to optimize the driver for this use case scenario.

The patch has been tested in the last few days on a x86 PC and a MIPS
set-top-box, with the PCTV 290e (digital only) and the Terratec Hybrid XS
(hybrid device). With the latter, I switched several times between analog and
digital mode (Kaffeine/TvTime) with no issue at all.
I unplugged/plugged the devices several times with no problem.
Also, after over 3 days of normal usage in the MPIS set-top-box, the PCTV 290e
was still up and running.
Signed-off-by: NGianluca Gennari <gennarone@gmail.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>
      86d38d1e
  7. 11 1月, 2012 1 次提交
  9. 19 10月, 2011 1 次提交
    • M
      [media] em28xx: implement VIDIOC_ENUM_FRAMESIZES · 1c5c5068
      由 Mauro Carvalho Chehab 提交于 
      Pidgin uses gstreamer (and libv4l) to work. Without implementing this ioctl,
it won't detect properly the size range, and driver will fail.

So, this patch is required, in order to use an em27xx webcam, like
Silvercrest.

The pigdin/gstreamer/libv4l needs to be fixed, as it shouldn't assume
that all drivers will implement this optional ioctl, but, at least now,
devices with em28xx have a better chance of working with pidgin.
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>
      1c5c5068
  11. 08 10月, 2011 1 次提交
  13. 18 9月, 2011 1 次提交
  15. 28 7月, 2011 1 次提交
    • M
      [media] Stop using linux/version.h on most video drivers · 1990d50b
      由 Mauro Carvalho Chehab 提交于 
      All the modified drivers didn't have any version increment since
Jan, 1 2011. Several of them didn't have any version increment
for a long time, even having new features and important bug fixes
happening.

As we're now filling the QUERYCAP version with the current Kernel
Release, we don't need to maintain a per-driver version control
anymore. So, let's just use the default.

In order to preserve the Kernel module version history, a
KERNEL_VERSION() macro were added to all modified drivers, and
the extraver number were incremented.

I opted to preserve the per-driver version control to a few
pwc, pvrusb2, s2255, s5p-fimc and sh_vou.

A few drivers are still using the legacy way to handle ioctl's.
So, we can't do such change on them, otherwise, they'll break.
Those are: uvc, et61x251 and sn9c102.

The rationale is that the per-driver version control seems to be
actively maintained on those.

Yet, I think that the better for them would be to just use the
default version numbering, instead of doing that by themselves.

While here, removed a few uneeded include linux/version.h
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>
      1990d50b
  17. 31 3月, 2011 1 次提交
  19. 22 3月, 2011 2 次提交
  21. 03 1月, 2011 1 次提交
  23. 30 12月, 2010 1 次提交
  25. 29 12月, 2010 1 次提交
  27. 21 10月, 2010 5 次提交
  29. 03 8月, 2010 1 次提交
  31. 19 5月, 2010 2 次提交
  33. 18 5月, 2010 1 次提交
  35. 30 3月, 2010 1 次提交
    • T
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
      由 Tejun Heo 提交于 
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      5a0e3ad6
  37. 27 2月, 2010 1 次提交
  39. 16 12月, 2009 5 次提交
  41. 06 12月, 2009 2 次提交
  43. 19 9月, 2009 8 次提交