From: Niko Tsirakis Date: Mon, 2 Oct 2023 20:47:09 +0000 (+0000) Subject: drm/i915/display/lspcon: Increase LSPCON mode settle timeout X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=cf37c0979e558213e2a2f87c2c3dfe644a66b210;p=linux.git drm/i915/display/lspcon: Increase LSPCON mode settle timeout This is to eliminate all cases of "*ERROR* LSPCON mode hasn't settled", followed by link training errors. Intel engineers recommended increasing this timeout and that does resolve the issue. On some CometLake-based device designs the Parade PS175 takes more than 400ms to settle in PCON mode. 100 reboot trials on one device resulted in a median settle time of 440ms and a maximum of 444ms. Even after increasing the timeout to 500ms, 2% of devices still had this error. So this increases the timeout to 800ms. Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9443 Signed-off-by: Pablo Ceballos Signed-off-by: Niko Tsirakis Reviewed-by: Jani Nikula Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/20231002204709.761089-1-ntsirakis@google.com --- diff --git a/drivers/gpu/drm/i915/display/intel_lspcon.c b/drivers/gpu/drm/i915/display/intel_lspcon.c index 152a22a8ffd25..1d048fa98561b 100644 --- a/drivers/gpu/drm/i915/display/intel_lspcon.c +++ b/drivers/gpu/drm/i915/display/intel_lspcon.c @@ -153,6 +153,18 @@ static enum drm_lspcon_mode lspcon_get_current_mode(struct intel_lspcon *lspcon) return current_mode; } +static int lspcon_get_mode_settle_timeout(struct intel_lspcon *lspcon) +{ + /* + * On some CometLake-based device designs the Parade PS175 takes more + * than 400ms to settle in PCON mode. 100 reboot trials on one device + * resulted in a median settle time of 440ms and a maximum of 444ms. + * Even after increasing the timeout to 500ms, 2% of devices still had + * this error. So this sets the timeout to 800ms. + */ + return lspcon->vendor == LSPCON_VENDOR_PARADE ? 800 : 400; +} + static enum drm_lspcon_mode lspcon_wait_mode(struct intel_lspcon *lspcon, enum drm_lspcon_mode mode) { @@ -167,7 +179,8 @@ static enum drm_lspcon_mode lspcon_wait_mode(struct intel_lspcon *lspcon, drm_dbg_kms(&i915->drm, "Waiting for LSPCON mode %s to settle\n", lspcon_mode_name(mode)); - wait_for((current_mode = lspcon_get_current_mode(lspcon)) == mode, 400); + wait_for((current_mode = lspcon_get_current_mode(lspcon)) == mode, + lspcon_get_mode_settle_timeout(lspcon)); if (current_mode != mode) drm_err(&i915->drm, "LSPCON mode hasn't settled\n");