On Tue, 10 Apr 2012 09:33:19 +0200, Daniel Vetter daniel.vetter@ffwll.ch wrote:
We've only computed whether we need to fall back to 6bpc due to dp link bandwidth constrains in mode_valid, but not mode_fixup. Under various circumstances X likes to create new modes which then lack proper 6bpc flags (if required), resulting in mode_fixup failures and ultimately black screens.
This is hopefully fixes the last regression fallout of the dp bandwidth fixes.
Based on my reading, this still leaves the issue of depth > 24 modes as the upper bandwidth required is calculated on the presumption of depth == 24, but the divider set to the fb depth in the normal case.
The likely culprit for this regression is
commit 3d794f87238f74d80e78a7611c7fbde8a54c85c2 Author: Keith Packard keithp@keithp.com Date: Wed Jan 25 08:16:25 2012 -0800
drm/i915: Force explicit bpp selection for intel_dp_link_requiredReported-and-tested-by: Brice Goglin Brice.Goglin@ens-lyon.org Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=48170 Cc: stable@kernel.org Signed-Off-by: Daniel Vetter daniel.vetter@ffwll.ch
drivers/gpu/drm/i915/intel_dp.c | 49 +++++++++++++++++++++++++++----------- 1 files changed, 35 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 110552f..065c26d 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -219,14 +219,38 @@ intel_dp_max_data_rate(int max_link_clock, int max_lanes) return (max_link_clock * max_lanes * 8) / 10; }
+static bool +intel_dp_adjust_dithering(struct intel_dp *intel_dp,
struct drm_display_mode *mode,struct drm_display_mode *adjusted_mode)+{
- int max_link_clock = intel_dp_link_clock(intel_dp_max_link_bw(intel_dp));
- int max_lanes = intel_dp_max_lane_count(intel_dp);
- int max_rate, mode_rate;
- mode_rate = intel_dp_link_required(mode->clock, 24);
- max_rate = intel_dp_max_data_rate(max_link_clock, max_lanes);
- if (mode_rate > max_rate) {
mode_rate = intel_dp_link_required(mode->clock, 18);
Cut'n'paste bad whitespace. -Chris