From f77772866385cd0a72311a9e2ac176214d2b0fa8 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Jouni=20H=C3=B6gander?= Date: Wed, 13 Mar 2024 15:32:21 +0200 Subject: [PATCH] drm/i915/display: Increase number of fast wake precharge pulses MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 --- 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 7e69be100d908..8a02d9cd2ec18 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c @@ -145,7 +145,13 @@ 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; -- 2.30.2