On Tue, 23 Jan 2018, Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> wrote: > On Tue, Jan 23, 2018 at 05:40:50PM +0000, Rodrigo Vivi wrote: >> Let's ignore VBT request if the pin is clearly wrong. >> >> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104139 >> Cc: Kai Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> >> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> > > Reviewed-by: Radhakrishna Sripada <radhakrishna.sripada@xxxxxxxxx> > (f2f) > thanks > > merged to dinq. A bit too fast IMO. The bug report doesn't include the vbt dump which you should *always* look at before making workarounds for vbt. Also, see below. >> --- >> drivers/gpu/drm/i915/intel_bios.c | 11 ++++++++--- >> 1 file changed, 8 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c >> index b0668202dc7e..95f0b310d656 100644 >> --- a/drivers/gpu/drm/i915/intel_bios.c >> +++ b/drivers/gpu/drm/i915/intel_bios.c >> @@ -1115,9 +1115,14 @@ static const u8 cnp_ddc_pin_map[] = { >> >> static u8 map_ddc_pin(struct drm_i915_private *dev_priv, u8 vbt_pin) >> { >> - if (HAS_PCH_CNP(dev_priv) && >> - vbt_pin > 0 && vbt_pin < ARRAY_SIZE(cnp_ddc_pin_map)) >> - return cnp_ddc_pin_map[vbt_pin]; >> + if (HAS_PCH_CNP(dev_priv)) { >> + if (vbt_pin > 0 && vbt_pin < ARRAY_SIZE(cnp_ddc_pin_map)) >> + return cnp_ddc_pin_map[vbt_pin]; >> + if (vbt_pin > GMBUS_PIN_4_CNP) { >> + DRM_DEBUG_KMS("Ignoring alternate pin: VBT claims DDC pin %d, which is not valid for this platform\n", vbt_pin); >> + return 0; >> + } The original code was wrong in the sense that it would only do the mapping if the provided vbt_pin was within bounds for CNP, and would return the unmapped vbt_pin otherwise. Instead, I think you should directly return 0 for out of bounds vbt_pin. This change here is effectively the same, but more confusing. As if there's a case where the vbt_pin can be both out of bounds, within CNP pin limits, and should be returned unmapped. That can't happen, so please make the code reflect that. BR, Jani. >> + } >> >> return vbt_pin; >> } >> -- >> 2.13.6 >> > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
