Bug#658662: drm/i915: no signal via DisplayPort on Sandy Bridge since Linux 3.2
tags 658662 + upstream patch moreinfo
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Hi again,
Peter Colberg wrote:
> cd9dde44f47501394b9f0715b6a36a92aa74c0d0 is the first bad commit
How about the attached patch --- does it work against the linux-3.2.y
branch?
Grateful,
Jonathan
From: Jesse Barnes <jbarnes@virtuousgeek.org>
Date: Thu, 21 Jun 2012 15:13:50 -0700
Subject: drm/i915: prefer wide & slow to fast & narrow in DP configs
commit 684aaa646f90f5ee07799d52d0735625756e607b upstream.
High frequency link configurations have the potential to cause trouble
with long and/or cheap cables, so prefer slow and wide configurations
instead. This patch has the potential to cause trouble for eDP
configurations that lie about available lanes, so if we run into that we
can make it conditional on eDP.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=45801
Tested-by: peter@colberg.org
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
drivers/gpu/drm/i915/intel_dp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index d4c4937067fb..fae2050324bc 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -708,8 +708,8 @@ intel_dp_mode_fixup(struct drm_encoder *encoder, struct drm_display_mode *mode,
bpp = adjusted_mode->private_flags & INTEL_MODE_DP_FORCE_6BPC ? 18 : 24;
- for (lane_count = 1; lane_count <= max_lane_count; lane_count <<= 1) {
- for (clock = 0; clock <= max_clock; clock++) {
+ for (clock = 0; clock <= max_clock; clock++) {
+ for (lane_count = 1; lane_count <= max_lane_count; lane_count <<= 1) {
int link_avail = intel_dp_max_data_rate(intel_dp_link_clock(bws[clock]), lane_count);
if (intel_dp_link_required(mode->clock, bpp)
--
1.7.11.rc3
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