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drm/i915: fix screen flickering

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Commit c9f038a1a5 ("drm/i915: Don't assume primary & cursor are
always on for wm calculation (v4)") fixes a null pointer dereference.
Setting the primary and cursor panes to false in
ilk_compute_wm_parameters to false does however give the following
errors in the kernel log and causes the screen to flicker.

[  101.133716] [drm:intel_set_cpu_fifo_underrun_reporting [i915]]
*ERROR* uncleared fifo underrun on pipe A
[  101.133725] [drm:intel_cpu_fifo_underrun_irq_handler [i915]]
*ERROR* CPU pipe A FIFO underrun

Always setting the panes to enabled fixes this error.

Helped-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Tested-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
This commit is contained in:
Thomas Gummerer 2015-05-14 09:16:39 +02:00 committed by Jani Nikula
parent e26081808e
commit 54da691deb
1 changed files with 11 additions and 13 deletions
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24
drivers/gpu/drm/i915/intel_pm.c
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@ -2045,22 +2045,20 @@ static void ilk_compute_wm_parameters(struct drm_crtc *crtc,
p->pipe_htotal = intel_crtc->config->base.adjusted_mode.crtc_htotal;
p->pixel_rate = ilk_pipe_pixel_rate(dev, crtc);
if (crtc->primary->state->fb) {
p->pri.enabled = true;
if (crtc->primary->state->fb)
p->pri.bytes_per_pixel =
crtc->primary->state->fb->bits_per_pixel / 8;
} else {
p->pri.enabled = false;
p->pri.bytes_per_pixel = 0;
}
else
p->pri.bytes_per_pixel = 4;
p->cur.bytes_per_pixel = 4;
/*
* TODO: for now, assume primary and cursor planes are always enabled.
* Setting them to false makes the screen flicker.
*/
p->pri.enabled = true;
p->cur.enabled = true;
if (crtc->cursor->state->fb) {
p->cur.enabled = true;
p->cur.bytes_per_pixel = 4;
} else {
p->cur.enabled = false;
p->cur.bytes_per_pixel = 0;
}
p->pri.horiz_pixels = intel_crtc->config->pipe_src_w;
p->cur.horiz_pixels = intel_crtc->base.cursor->state->crtc_w;