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. > > > > >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 <[email protected]> > >> Cc: Rodrigo Vivi <[email protected]> > >> Cc: Mika Kuoppala <[email protected]> > >> Cc: Jani Nikula <[email protected]> > >> Cc: William Tseng <[email protected]> > >> Cc: Cooper Chiou <[email protected]> > >> Signed-off-by: Lee Shawn C <[email protected]> > >> --- > >> 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 -- Ville Syrjälä Intel _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
