* FAILED: patch "[PATCH] drm/i915/edp: don't write to DP_LINK_BW_SET when using rate" failed to apply to 6.6-stable tree
@ 2023-12-18 7:19 gregkh
0 siblings, 0 replies; only message in thread
From: gregkh @ 2023-12-18 7:19 UTC (permalink / raw)
To: jani.nikula, animesh.manna, uma.shankar, ville.syrjala; +Cc: stable
The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x e6861d8264cd43c5eb20196e53df36fd71ec5698
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023121841-backspin-troubling-44cf@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
e6861d8264cd ("drm/i915/edp: don't write to DP_LINK_BW_SET when using rate select")
3072a24c778a ("drm/i915: Introduce crtc_state->enhanced_framing")
3dfeb80b3088 ("drm/i915: Fix FEC state dump")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e6861d8264cd43c5eb20196e53df36fd71ec5698 Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula@intel.com>
Date: Tue, 5 Dec 2023 20:05:51 +0200
Subject: [PATCH] drm/i915/edp: don't write to DP_LINK_BW_SET when using rate
select
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
The eDP 1.5 spec adds a clarification for eDP 1.4x:
> For eDP v1.4x, if the Source device chooses the Main-Link rate by way
> of DPCD 00100h, the Sink device shall ignore DPCD 00115h[2:0].
We write 0 to DP_LINK_BW_SET (DPCD 100h) even when using
DP_LINK_RATE_SET (DPCD 114h). Stop doing that, as it can cause the panel
to ignore the rate set method.
Moreover, 0 is a reserved value for DP_LINK_BW_SET, and should not be
used.
v2: Improve the comments (Ville)
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9081
Tested-by: Animesh Manna <animesh.manna@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231205180551.2476228-1-jani.nikula@intel.com
(cherry picked from commit 23b392b94acb0499f69706c5808c099f590ebcf4)
Cc: stable@vger.kernel.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index dbc1b66c8ee4..1abfafbbfa75 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -650,19 +650,30 @@ intel_dp_update_link_bw_set(struct intel_dp *intel_dp,
const struct intel_crtc_state *crtc_state,
u8 link_bw, u8 rate_select)
{
- u8 link_config[2];
+ u8 lane_count = crtc_state->lane_count;
- /* Write the link configuration data */
- link_config[0] = link_bw;
- link_config[1] = crtc_state->lane_count;
if (crtc_state->enhanced_framing)
- link_config[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
- drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_BW_SET, link_config, 2);
+ lane_count |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
- /* eDP 1.4 rate select method. */
- if (!link_bw)
- drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_RATE_SET,
- &rate_select, 1);
+ if (link_bw) {
+ /* DP and eDP v1.3 and earlier link bw set method. */
+ u8 link_config[] = { link_bw, lane_count };
+
+ drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_BW_SET, link_config,
+ ARRAY_SIZE(link_config));
+ } else {
+ /*
+ * eDP v1.4 and later link rate set method.
+ *
+ * eDP v1.4x sinks shall ignore DP_LINK_RATE_SET if
+ * DP_LINK_BW_SET is set. Avoid writing DP_LINK_BW_SET.
+ *
+ * eDP v1.5 sinks allow choosing either, and the last choice
+ * shall be active.
+ */
+ drm_dp_dpcd_writeb(&intel_dp->aux, DP_LANE_COUNT_SET, lane_count);
+ drm_dp_dpcd_writeb(&intel_dp->aux, DP_LINK_RATE_SET, rate_select);
+ }
}
/*
^ permalink raw reply related [flat|nested] only message in thread
only message in thread, other threads:[~2023-12-18 7:19 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-12-18 7:19 FAILED: patch "[PATCH] drm/i915/edp: don't write to DP_LINK_BW_SET when using rate" failed to apply to 6.6-stable tree gregkh
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.