Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1449462

Re: [PATCH v2 1/4] drm/i915/gen9: Only copy WM results for changed pipes to skl_hw

Show all headers | View raw

Op 21-07-16 om 21:23 schreef Lyude:
> From: Matt Roper <matthew.d.roper@intel.com>
>
> When we write watermark values to the hardware, those values are stored
> in dev_priv->wm.skl_hw.  However with recent watermark changes, the
> results structure we're copying from only contains valid watermark and
> DDB values for the pipes that are actually changing; the values for
> other pipes remain 0.  Thus a blind copy of the entire skl_wm_values
> structure will clobber the values for unchanged pipes...we need to be
> more selective and only copy over the values for the changing pipes.
>
> This mistake was hidden until recently due to another bug that caused us
> to erroneously re-calculate watermarks for all active pipes rather than
> changing pipes.  Only when that bug was fixed was the impact of this bug
> discovered (e.g., modesets failing with "Requested display configuration
> exceeds system watermark limitations" messages and leaving watermarks
> non-functional, even ones initiated by intel_fbdev_restore_mode).
>
> Changes since v1:
>  - Add a function for copying a pipe's wm values
>    (skl_copy_wm_for_pipe()) so we can reuse this later
Looks like I can hit this when I wrote some tests for patch 2 in this series.

testcase will be kms_cursor_legacy.2x-flip-vs-cursor-legacy, but I haven't committed the changes yet.

Back to linux.kernel | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

[PATCH v2 1/4] drm/i915/gen9: Only copy WM results for changed pipes to skl_hw Lyude <cpaul@redhat.com> - 2016-07-21 21:30 +0200
  Re: [PATCH v2 1/4] drm/i915/gen9: Only copy WM results for changed  pipes to skl_hw Maarten Lankhorst <maarten.lankhorst@linux.intel.com> - 2016-07-25 15:10 +0200

csiph-web