The patch below does not apply to the 6.1-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@xxxxxxxxxxxxxxx>. 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-6.1.y git checkout FETCH_HEAD git cherry-pick -x e6861d8264cd43c5eb20196e53df36fd71ec5698 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023121842-qualm-bootie-5c96@gregkh' --subject-prefix 'PATCH 6.1.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") f60500f31e99 ("drm/i915/display/dp: 128/132b LT requirement") 23ef61946374 ("drm/i915/mtl/display: Implement DisplayPort sequences") 51390cc0e00a ("drm/i915/mtl: Add Support for C10 PHY message bus and pll programming") a42e65f33c38 ("drm/i915/mtl: Create separate reg file for PICA registers") 99cfbed19d06 ("drm/i915/vrr: Relocate VRR enable/disable") ecaeecea9263 ("drm/i915/vrr: Tell intel_crtc_update_active_timings() about VRR explicitly") fa9e4fce52ec ("drm/i915/vrr: Make delayed vblank operational in VRR mode on adl/dg2") b25e07419fee ("drm/i915/vrr: Eliminate redundant function arguments") 6a9856075563 ("drm/i915: Generalize planes_{enabling,disabling}()") 57b5482bff9e ("drm/i915: Introduce intel_csc_matrix struct") c5de248484af ("drm/i915/dpt: Add a modparam to disable DPT via the chicken bit") 5a08585d38d6 ("drm/i915: Add PLANE_CHICKEN registers") 1a324a40b452 ("i915/display/dp: SDP CRC16 for 128b132b link layer") b5202a93cd37 ("drm/i915: Extract intel_crtc_scanline_offset()") 84f4ebe8c1ab ("drm/i915: Relocate intel_crtc_update_active_timings()") 6e8acb6686d8 ("drm/i915: Add belts and suspenders locking for seamless M/N changes") 8cb1f95cca68 ("drm/i915: Update vblank timestamping stuff on seamless M/N change") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From e6861d8264cd43c5eb20196e53df36fd71ec5698 Mon Sep 17 00:00:00 2001 From: Jani Nikula <jani.nikula@xxxxxxxxx> 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@xxxxxxxxx> Reviewed-by: Uma Shankar <uma.shankar@xxxxxxxxx> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20231205180551.2476228-1-jani.nikula@xxxxxxxxx (cherry picked from commit 23b392b94acb0499f69706c5808c099f590ebcf4) Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> 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); + } } /*
