From 54da691deb123c045259ebf4f5c67381244f58f1 Mon Sep 17 00:00:00 2001 From: Thomas Gummerer Date: Thu, 14 May 2015 09:16:39 +0200 Subject: drm/i915: fix screen flickering Commit c9f038a1a592 ("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 Signed-off-by: Thomas Gummerer Reviewed-by: Matt Roper Tested-by: Mario Kleiner Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/intel_pm.c | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index fa4ccb346389..555b896d2bda 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -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; -- cgit v1.2.3-59-g8ed1b