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  1. 22 8月, 2016 1 次提交
    • L
      drm/i915/skl: Add support for the SAGV, fix underrun hangs · f4033726
      由 Lyude 提交于 
      Since the watermark calculations for Skylake are still broken, we're apt
to hitting underruns very easily under multi-monitor configurations.
While it would be lovely if this was fixed, it's not. Another problem
that's been coming from this however, is the mysterious issue of
underruns causing full system hangs. An easy way to reproduce this with
a skylake system:

- Get a laptop with a skylake GPU, and hook up two external monitors to
  it
- Move the cursor from the built-in LCD to one of the external displays
  as quickly as you can
- You'll get a few pipe underruns, and eventually the entire system will
  just freeze.

After doing a lot of investigation and reading through the bspec, I
found the existence of the SAGV, which is responsible for adjusting the
system agent voltage and clock frequencies depending on how much power
we need. According to the bspec:

"The display engine access to system memory is blocked during the
 adjustment time. SAGV defaults to enabled. Software must use the
 GT-driver pcode mailbox to disable SAGV when the display engine is not
 able to tolerate the blocking time."

The rest of the bspec goes on to explain that software can simply leave
the SAGV enabled, and disable it when we use interlaced pipes/have more
then one pipe active.

Sure enough, with this patchset the system hangs resulting from pipe
underruns on Skylake have completely vanished on my T460s. Additionally,
the bspec mentions turning off the SAGV	with more then one pipe enabled
as a workaround for display underruns. While this patch doesn't entirely
fix that, it looks like it does improve the situation a little bit so
it's likely this is going to be required to make watermarks on Skylake
fully functional.

This will still need additional work in the future: we shouldn't be
enabling the SAGV if any of the currently enabled planes can't enable WM
levels that introduce latencies >= 30 µs.

Changes since v11:
 - Add skl_can_enable_sagv()
 - Make sure we don't enable SAGV when not all planes can enable
   watermarks >= the SAGV engine block time. I was originally going to
   save this for later, but I recently managed to run into a machine
   that was having problems with a single pipe configuration + SAGV.
 - Make comparisons to I915_SKL_SAGV_NOT_CONTROLLED explicit
 - Change I915_SAGV_DYNAMIC_FREQ to I915_SAGV_ENABLE
 - Move printks outside of mutexes
 - Don't print error messages twice
Changes since v10:
 - Apparently sandybridge_pcode_read actually writes values and reads
   them back, despite it's misleading function name. This means we've
   been doing this mostly wrong and have been writing garbage to the
   SAGV control. Because of this, we no longer attempt to read the SAGV
   status during initialization (since there are no helpers for this).
 - mlankhorst noticed that this patch was breaking on some very early
   pre-release Skylake machines, which apparently don't allow you to
   disable the SAGV. To prevent machines from failing tests due to SAGV
   errors, if the first time we try to control the SAGV results in the
   mailbox indicating an invalid command, we just disable future attempts
   to control the SAGV state by setting dev_priv->skl_sagv_status to
   I915_SKL_SAGV_NOT_CONTROLLED and make a note of it in dmesg.
 - Move mutex_unlock() a little higher in skl_enable_sagv(). This
   doesn't actually fix anything, but lets us release the lock a little
   sooner since we're finished with it.
Changes since v9:
 - Only enable/disable sagv on Skylake
Changes since v8:
 - Add intel_state->modeset guard to the conditional for
   skl_enable_sagv()
Changes since v7:
 - Remove GEN9_SAGV_LOW_FREQ, replace with GEN9_SAGV_IS_ENABLED (that's
   all we use it for anyway)
 - Use GEN9_SAGV_IS_ENABLED instead of 0x1 for clarification
 - Fix a styling error that snuck past me
Changes since v6:
 - Protect skl_enable_sagv() with intel_state->modeset conditional in
   intel_atomic_commit_tail()
Changes since v5:
 - Don't use is_power_of_2. Makes things confusing
 - Don't use the old state to figure out whether or not to
   enable/disable the sagv, use the new one
 - Split the loop in skl_disable_sagv into it's own function
 - Move skl_sagv_enable/disable() calls into intel_atomic_commit_tail()
Changes since v4:
 - Use is_power_of_2 against active_crtcs to check whether we have > 1
   pipe enabled
 - Fix skl_sagv_get_hw_state(): (temp & 0x1) indicates disabled, 0x0
   enabled
 - Call skl_sagv_enable/disable() from pre/post-plane updates
Changes since v3:
 - Use time_before() to compare timeout to jiffies
Changes since v2:
 - Really apply minor style nitpicks to patch this time
Changes since v1:
 - Added comments about this probably being one of the requirements to
   fixing Skylake's watermark issues
 - Minor style nitpicks from Matt Roper
 - Disable these functions on Broxton, since it doesn't have an SAGV
Signed-off-by: NLyude <cpaul@redhat.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1471463761-26796-3-git-send-email-cpaul@redhat.com
[mlankhorst: ENOSYS -> ENXIO, whitespace fixes]

(cherry picked from commit 656d1b89)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
      f4033726
  3. 11 8月, 2016 1 次提交
  5. 09 8月, 2016 1 次提交
    • M
      drm/i915/dp: Revert "drm/i915/dp: fall back to 18 bpp when sink capability is unknown" · 196f954e
      由 Mario Kleiner 提交于 
      This reverts commit 013dd9e0
("drm/i915/dp: fall back to 18 bpp when sink capability is unknown")

This commit introduced a regression into stable kernels,
as it reduces output color depth to 6 bpc for any video
sink connected to a Displayport connector if that sink
doesn't report a specific color depth via EDID, or if
our EDID parser doesn't actually recognize the proper
bpc from EDID.

Affected are active DisplayPort->VGA converters and
active DisplayPort->DVI converters. Both should be
able to handle 8 bpc, but are degraded to 6 bpc with
this patch.

The reverted commit was meant to fix
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=105331

A followup patch implements a fix for that specific bug,
which is caused by a faulty EDID of the affected DP panel
by adding a new EDID quirk for that panel.

DP 18 bpp fallback handling and other improvements to
DP sink bpc detection will be handled for future
kernels in a separate series of patches.

Please backport to stable.
Signed-off-by: NMario Kleiner <mario.kleiner.de@gmail.com>
Acked-by: NJani Nikula <jani.nikula@intel.com>
Cc: stable@vger.kernel.org
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>
      196f954e
  7. 30 7月, 2016 1 次提交
  9. 19 7月, 2016 1 次提交
  11. 18 7月, 2016 1 次提交
  13. 08 7月, 2016 1 次提交
  15. 07 7月, 2016 8 次提交
  17. 05 7月, 2016 1 次提交
  19. 04 7月, 2016 3 次提交
  21. 03 7月, 2016 1 次提交
  23. 02 7月, 2016 1 次提交
    • C
      drm/i915: Spin after waking up for an interrupt · f69a02c9
      由 Chris Wilson 提交于 
      When waiting for an interrupt (waiting for the engine to complete some
work), we know we are the only waiter to be woken on this engine. We also
know when the GPU has nearly completed our request (or at least started
processing it), so after being woken and we detect that the GPU is
active and working on our request, allow us the bottom-half (the first
waiter who wakes up to handle checking the seqno after the interrupt) to
spin for a very short while to reduce client latencies.

The impact is minimal, there was an improvement to the realtime-vs-many
clients case, but exporting the function proves useful later. However,
it is tempting to adjust irq_seqno_barrier to include the spin. The
problem is first ensuring that the "start-of-request" seqno is coherent
as we use that as our basis for judging when it is ok to spin. If we
could, spinning there could dramatically shorten some sleeps, and allow
us to make the barriers more conservative to handle missed seqno writes
on more platforms (all gen7+ are known to have the occasional issue, at
least).
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1467390209-3576-7-git-send-email-chris@chris-wilson.co.uk
      f69a02c9
  25. 30 6月, 2016 17 次提交
  27. 29 6月, 2016 2 次提交