Hi, On Wed, Jan 16, 2019 at 05:33:19PM -0800, Dhinakaran Pandiyan wrote: > On Thu, 2018-12-20 at 17:52 +0200, Imre Deak wrote: > > VBT may include incorrect information about the presence of port F. > > Work > > around this on SKUs where we know the port is not present. > > If we cannot trust the data in VBT, can we not test for the absence of > port-F by enabling the powerwell and checking for a timeout? Or at > least mark up a non-existent port after the first timeout so that we > don't keep probing it.
Yes, thought about it too, but I'm not sure if it's a good idea. Enabling power wells has unexpected (at least to me) side effects on ICL, so I'd rather avoid using that as a detection method. OTOH the PCI ID list with fused-off ports must be well-defined and known, there just seems to be a difficulty to get at that list internally. So instead I'd suggest pushing for getting that list added to BSpec. I opened already a change request in BSpec for that, but more poking would be good. > > This patch is an improvement over checking the VBT for all ports, so > Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandi...@intel.com> Thanks for the review. > > > > > v2: > > - Fix IS_ICL_WITH_PORT_F, so it's useable from any context. > > > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108915 > > Cc: Mika Kahola <mika.kah...@intel.com> > > Cc: Jani Nikula <jani.nik...@linux.intel.com> > > Signed-off-by: Imre Deak <imre.d...@intel.com> > > --- > > drivers/gpu/drm/i915/i915_drv.h | 2 ++ > > drivers/gpu/drm/i915/intel_display.c | 4 +++- > > 2 files changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/i915/i915_drv.h > > b/drivers/gpu/drm/i915/i915_drv.h > > index 815db160b966..e45cda9d9555 100644 > > --- a/drivers/gpu/drm/i915/i915_drv.h > > +++ b/drivers/gpu/drm/i915/i915_drv.h > > @@ -2317,6 +2317,8 @@ intel_info(const struct drm_i915_private > > *dev_priv) > > (dev_priv)->info.gt == 3) > > #define IS_CNL_WITH_PORT_F(dev_priv) (IS_CANNONLAKE(dev_priv) && \ > > (INTEL_DEVID(dev_priv) & > > 0x0004) == 0x0004) > > +#define IS_ICL_WITH_PORT_F(dev_priv) (IS_ICELAKE(dev_priv) && \ > > + INTEL_DEVID(dev_priv) != > > 0x8A51) > > > > #define IS_ALPHA_SUPPORT(intel_info) ((intel_info)- > > >is_alpha_support) > > > > diff --git a/drivers/gpu/drm/i915/intel_display.c > > b/drivers/gpu/drm/i915/intel_display.c > > index 2b81da068010..bd7fdaf7e093 100644 > > --- a/drivers/gpu/drm/i915/intel_display.c > > +++ b/drivers/gpu/drm/i915/intel_display.c > > @@ -14276,8 +14276,10 @@ static void intel_setup_outputs(struct > > drm_i915_private *dev_priv) > > /* > > * On some ICL SKUs port F is not present. No strap > > bits for > > * this, so rely on VBT. > > + * Work around broken VBTs on SKUs known to have no > > port F. > > */ > > - if (intel_bios_is_port_present(dev_priv, PORT_F)) > > + if (IS_ICL_WITH_PORT_F(dev_priv) && > > + intel_bios_is_port_present(dev_priv, PORT_F)) > > intel_ddi_init(dev_priv, PORT_F); > > > > icl_dsi_init(dev_priv); > _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
