From 1d395ab43e6bffdca1845feba351eb8f8629dc88 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jouni=20H=C3=B6gander?= Date: Tue, 16 Apr 2024 14:04:16 +0800 Subject: [PATCH] drm/i915/display: Increase number of fast wake precharge pulses MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit BugLink: https://bugs.launchpad.net/bugs/2046315 Increasing number of fast wake sync pulses seem to fix problems with certain PSR panels. This should be ok for other panels as well as the eDP specification allows 10...16 precharge pulses and we are still within that range. v3: mention laptop model and panel manufacturer and model in comment v2: add comment explaining pulse count is increased Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9739 Signed-off-by: Jouni Högander Acked-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20240313133221.868391-5-jouni.hogander@intel.com (cherry picked from commit f77772866385cd0a72311a9e2ac176214d2b0fa8 linux-next) Signed-off-by: Hui Wang Acked-by: Timo Aaltonen Acked-by: Guoqing Jiang Signed-off-by: Roxana Nicolescu --- drivers/gpu/drm/i915/display/intel_dp_aux.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c index 375a94b3d455..375cce5bfc68 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c @@ -144,7 +144,13 @@ static int intel_dp_aux_sync_len(void) int intel_dp_aux_fw_sync_len(void) { - int precharge = 10; /* 10-16 */ + /* + * We faced some glitches on Dell Precision 5490 MTL laptop with panel: + * "Manufacturer: AUO, Model: 63898" when using HW default 18. Using 20 + * is fixing these problems with the panel. It is still within range + * mentioned in eDP specification. + */ + int precharge = 12; /* 10-16 */ int preamble = 8; return precharge + preamble;