On Tue, Sept. 15, 2020, 1:35 p.m. Ville Syrjälä wrote: >On Tue, Sep 15, 2020 at 01:18:13PM +0000, Lee, Shawn C wrote: >> On Fri, Sept. 11, 2020, 2:21 p.m. Ville Syrjälä wrote: >> >On Thu, Aug 27, 2020 at 01:51:29PM +0800, Lee Shawn C wrote: >> >> Customer report random display flicker issue on Nightfury board. >> >> And we found this problem might be caused by VT-d and FBC are both >> >> enabled. According to sighting report, it recommend to turn >> >> drm/i915/fbc: disable FBC on Nightfury board >> >> >> >> Customer report random display flicker issue on Nightfury board. >> >> And we found this problem might be caused by VT-d and FBC are both >> >> enabled. According to sighting report, it recommend to turn FBC off to >> >> workaround this kind of issue. >> >> >> >> This change refer to DMI BOARD_VENDOR and BOARD_NAME information to >> >> disable FBC. >> > >> >What is this "nightfury board" exactly? >> >> It is chrome os project on CML platform. The board name is "nightfury". > >OK, then someone should definitely test if that missing w/a >fixes the underruns. Customer already confirmed display flicker issue disappear after applied this w/a. BTW, here is the patch v2 to fix some typo in v1. https://patchwork.freedesktop.org/series/81087/#rev2 Best regards, Shawn > >> >> > >> >I think we're missing at least one fbc vs. vt-d w/a on some kbl/cfl/etc. era platforms: >> >git://github.com/vsyrjala/linux.git vtd_wa_1142 >> > >> >> >> >> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> >> >> Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> >> >> Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx> >> >> Cc: Jani Nikula <jani.nikula@xxxxxxxxx> >> >> Cc: William Tseng <william.tseng@xxxxxxxxx> >> >> Cc: Cooper Chiou <cooper.chiou@xxxxxxxxx> >> >> Signed-off-by: Lee Shawn C <shawn.c.lee@xxxxxxxxx> >> >> --- >> >> drivers/gpu/drm/i915/display/intel_fbc.c | 22 ++++++++++++++++++++++ >> >> 1 file changed, 22 insertions(+) >> >> >> >> diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c >> >> b/drivers/gpu/drm/i915/display/intel_fbc.c >> >> index 327af428d73f..20660fdbab36 100644 >> >> --- a/drivers/gpu/drm/i915/display/intel_fbc.c >> >> +++ b/drivers/gpu/drm/i915/display/intel_fbc.c >> >> @@ -39,6 +39,7 @@ >> >> */ >> >> >> >> #include <drm/drm_fourcc.h> >> >> +#include <linux/dmi.h> >> >> >> >> #include "i915_drv.h" >> >> #include "i915_trace.h" >> >> @@ -1439,6 +1440,24 @@ static int intel_sanitize_fbc_option(struct drm_i915_private *dev_priv) >> >> return 0; >> >> } >> >> >> >> +static int intel_fbc_vtd_callback(const struct dmi_system_id *id) { >> >> + DRM_DEBUG_KMS("Disabling FBC to prevent screen flicker on %s device\n", id->ident); >> >> + return 1; >> >> +} >> >> + >> >> +static const struct dmi_system_id intel_fbc_vtd_detect[] = { >> >> + { >> >> + .callback = intel_fbc_vtd_callback, >> >> + .ident = "Google Nightfury", >> >> + .matches = { >> >> + DMI_MATCH(DMI_BOARD_VENDOR, "Google"), >> >> + DMI_MATCH(DMI_BOARD_NAME, "Nightfury"), >> >> + }, >> >> + }, >> >> + { } >> >> +}; >> >> + >> >> static bool need_fbc_vtd_wa(struct drm_i915_private *dev_priv) { >> >> /* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl,bxt */ @@ -1450,6 +1469,9 >> >> @@ static bool need_fbc_vtd_wa(struct drm_i915_private *dev_priv) >> >> return true; >> >> } >> >> >> >> + if (dmi_check_system(intel_fbc_vtd_detect)) >> >> + return true; >> >> + >> >> return false; >> >> } >> >> >> >> -- >> >> 2.17.1 >> > >> >-- >> >Ville Syrjälä >> >Intel >> >> Best regards, >> Shawn _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
