lkml.org 
[lkml]   [2016]   [Jul]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v2 1/4] drm/i915/gen9: Only copy WM results for changed pipes to skl_hw
From
Date
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.

\
 
 \ /
  Last update: 2016-07-25 15:41    [W:1.071 / U:0.032 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site