On Thu, 18 May 2017, "Pandiyan, Dhinakaran" <dhinakaran.pandiyan@xxxxxxxxx> wrote: > On Thu, 2017-05-18 at 14:10 +0300, Jani Nikula wrote: >> Face the fact, there are Display Port sink and branch devices out there >> in the wild that don't follow the Display Port specifications, or they >> have bugs, or just otherwise require special treatment. Start a common >> quirk database the drivers can query based on the DP device >> identification. At least for now, we leave the workarounds for the >> drivers to implement as they see fit. >> >> For starters, add a branch device that can't handle full 24-bit main >> link Mdiv and Ndiv main link attributes properly. Naturally, the >> workaround of reducing main link attributes for all devices ended up in >> regressions for other devices. So here we are. >> >> v2: Rebase on DRM DP desc read helpers >> >> v3: Fix the OUI memcmp blunder (Clint) >> >> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> >> Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx> >> Cc: Clint Taylor <clinton.a.taylor@xxxxxxxxx> >> Cc: Adam Jackson <ajax@xxxxxxxxxx> >> Cc: Harry Wentland <harry.wentland@xxxxxxx> >> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> >> --- >> drivers/gpu/drm/drm_dp_helper.c | 52 +++++++++++++++++++++++++++++++++++++++-- >> include/drm/drm_dp_helper.h | 32 +++++++++++++++++++++++++ >> 2 files changed, 82 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c >> index 52e0ca9a5bb1..213fb837e1c4 100644 >> --- a/drivers/gpu/drm/drm_dp_helper.c > > <snip> >> + * enum drm_dp_quirk - Display Port sink/branch device specific quirks >> + * >> + * Display Port sink and branch devices in the wild have a variety of bugs, try >> + * to collect them here. The quirks are shared, but it's up to the drivers to >> + * implement workarounds for them. >> + */ >> +enum drm_dp_quirk { >> + /** >> + * @DP_DPCD_QUIRK_LIMITED_M_N: >> + * >> + * The device requires main link attributes Mdiv and Ndiv to be limited > > s/Mdiv/Mvid > s/Ndiv/Nvid Thanks, I took the liberty of fixing this while applying. BR, Jani. > >> + * to 16 bits. >> + */ >> + DP_DPCD_QUIRK_LIMITED_M_N, >> +}; -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel