Re: [PATCH] drm/i915: Store 9 bits of PCI Device ID for platforms with a LP PCH

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Fri, Jun 16, 2017 at 10:58:57PM +0300, Imre Deak wrote:
> On Fri, Jun 16, 2017 at 10:19:34PM +0300, Pandiyan, Dhinakaran wrote:
> > On Fri, 2017-06-16 at 16:26 +0300, Imre Deak wrote:
> > > On Thu, Jun 15, 2017 at 01:56:47PM -0700, Dhinakaran Pandiyan wrote:
> > > > Although we use 9 bits of Device ID for identifying PCH, only 8 bits are
> > > > stored in dev_priv->pch_id. This makes HAS_PCH_CNP_LP() and
> > > > HAS_PCH_SPT_LP() incorrect. Fix this by storing all the 9 bits for the
> > > > platforms with LP PCH.
> > > > 
> > > > Also, use the extended 9 bits for detecting PCH_LPT_LP.
> > > > 
> > > > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > > > Cc: Jani Nikula <jani.nikula@intel.com>
> > > > Cc: Imre Deak <imre.deak@intel.com>
> > > > Fixes: commit ec7e0bb35f8d ("drm/i915/cnp: Add PCI ID for Cannonpoint LP PCH")
> > > > Reported-by: Imre Deak <imre.deak@intel.com>
> > > > Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
> > > > ---
> > > >  drivers/gpu/drm/i915/i915_drv.c | 15 ++++++++++++---
> > > >  1 file changed, 12 insertions(+), 3 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> > > > index 1f802de..29caf05 100644
> > > > --- a/drivers/gpu/drm/i915/i915_drv.c
> > > > +++ b/drivers/gpu/drm/i915/i915_drv.c
> > > > @@ -176,31 +176,34 @@ static void intel_detect_pch(struct drm_i915_private *dev_priv)
> > > >  			unsigned short id_ext = pch->device &
> > > >  				INTEL_PCH_DEVICE_ID_MASK_EXT;
> > > >  
> > > > -			dev_priv->pch_id = id;
> > > > -
> > > >  			if (id == INTEL_PCH_IBX_DEVICE_ID_TYPE) {
> > > > +				dev_priv->pch_id = id;
> > > >  				dev_priv->pch_type = PCH_IBX;
> > > >  				DRM_DEBUG_KMS("Found Ibex Peak PCH\n");
> > > >  				WARN_ON(!IS_GEN5(dev_priv));
> > > >  			} else if (id == INTEL_PCH_CPT_DEVICE_ID_TYPE) {
> > > > +				dev_priv->pch_id = id;
> > > >  				dev_priv->pch_type = PCH_CPT;
> > > >  				DRM_DEBUG_KMS("Found CougarPoint PCH\n");
> > > >  				WARN_ON(!(IS_GEN6(dev_priv) ||
> > > >  					IS_IVYBRIDGE(dev_priv)));
> > > >  			} else if (id == INTEL_PCH_PPT_DEVICE_ID_TYPE) {
> > > >  				/* PantherPoint is CPT compatible */
> > > > +				dev_priv->pch_id = id;
> > > >  				dev_priv->pch_type = PCH_CPT;
> > > >  				DRM_DEBUG_KMS("Found PantherPoint PCH\n");
> > > >  				WARN_ON(!(IS_GEN6(dev_priv) ||
> > > >  					IS_IVYBRIDGE(dev_priv)));
> > > >  			} else if (id == INTEL_PCH_LPT_DEVICE_ID_TYPE) {
> > > > +				dev_priv->pch_id = id;
> > > >  				dev_priv->pch_type = PCH_LPT;
> > > >  				DRM_DEBUG_KMS("Found LynxPoint PCH\n");
> > > >  				WARN_ON(!IS_HASWELL(dev_priv) &&
> > > >  					!IS_BROADWELL(dev_priv));
> > > >  				WARN_ON(IS_HSW_ULT(dev_priv) ||
> > > >  					IS_BDW_ULT(dev_priv));
> > > > -			} else if (id == INTEL_PCH_LPT_LP_DEVICE_ID_TYPE) {
> > > > +			} else if (id_ext == INTEL_PCH_LPT_LP_DEVICE_ID_TYPE) {
> > > > +				dev_priv->pch_id = id_ext;
> > > 
> > > Hm, why to change it? Is there any info about the PCI_DEVICE_ID format
> > > for these Intel PCH devices? It looks like all the existing ones use
> > > less than 8 bits for some kind of HW patch level, but would be good to
> > > have some documentation about this. Anyway if this is need it should be
> > > a separate patch.
> > 
> > I found a document that says 9 bits of Dev ID are needed for
> > identification. Also, I see references for "Wildcat Point-LP" pch
> > devices starting with a Dev ID 0x9c8 elsewhere in the kernel (LPT-LP is
> > 0x9c0).
> 
> Ok, if that doc applies to all PCHs we use I'd suggest a follow-up patch
> to this one that changes all of them to 9 bits and adds a reference to the
> document.

I think 9 bits would require that we deal with WPT explicitly.

> 
> > > 
> > > Without this part the rest looks ok to me:
> > > Reviewed-by: Imre Deak <imre.deak@intel.com>
> > > 
> > 
> > Thanks for the review, I'll drop the change since I am not sure how
> > useful it is.
> > 
> > 
> > > >  				dev_priv->pch_type = PCH_LPT;
> > > >  				DRM_DEBUG_KMS("Found LynxPoint LP PCH\n");
> > > >  				WARN_ON(!IS_HASWELL(dev_priv) &&
> > > > @@ -208,26 +211,31 @@ static void intel_detect_pch(struct drm_i915_private *dev_priv)
> > > >  				WARN_ON(!IS_HSW_ULT(dev_priv) &&
> > > >  					!IS_BDW_ULT(dev_priv));
> > > >  			} else if (id == INTEL_PCH_SPT_DEVICE_ID_TYPE) {
> > > > +				dev_priv->pch_id = id;
> > > >  				dev_priv->pch_type = PCH_SPT;
> > > >  				DRM_DEBUG_KMS("Found SunrisePoint PCH\n");
> > > >  				WARN_ON(!IS_SKYLAKE(dev_priv) &&
> > > >  					!IS_KABYLAKE(dev_priv));
> > > >  			} else if (id_ext == INTEL_PCH_SPT_LP_DEVICE_ID_TYPE) {
> > > > +				dev_priv->pch_id = id_ext;
> > > >  				dev_priv->pch_type = PCH_SPT;
> > > >  				DRM_DEBUG_KMS("Found SunrisePoint LP PCH\n");
> > > >  				WARN_ON(!IS_SKYLAKE(dev_priv) &&
> > > >  					!IS_KABYLAKE(dev_priv));
> > > >  			} else if (id == INTEL_PCH_KBP_DEVICE_ID_TYPE) {
> > > > +				dev_priv->pch_id = id;
> > > >  				dev_priv->pch_type = PCH_KBP;
> > > >  				DRM_DEBUG_KMS("Found KabyPoint PCH\n");
> > > >  				WARN_ON(!IS_SKYLAKE(dev_priv) &&
> > > >  					!IS_KABYLAKE(dev_priv));
> > > >  			} else if (id == INTEL_PCH_CNP_DEVICE_ID_TYPE) {
> > > > +				dev_priv->pch_id = id;
> > > >  				dev_priv->pch_type = PCH_CNP;
> > > >  				DRM_DEBUG_KMS("Found CannonPoint PCH\n");
> > > >  				WARN_ON(!IS_CANNONLAKE(dev_priv) &&
> > > >  					!IS_COFFEELAKE(dev_priv));
> > > >  			} else if (id_ext == INTEL_PCH_CNP_LP_DEVICE_ID_TYPE) {
> > > > +				dev_priv->pch_id = id_ext;
> > > >  				dev_priv->pch_type = PCH_CNP;
> > > >  				DRM_DEBUG_KMS("Found CannonPoint LP PCH\n");
> > > >  				WARN_ON(!IS_CANNONLAKE(dev_priv) &&
> > > > @@ -239,6 +247,7 @@ static void intel_detect_pch(struct drm_i915_private *dev_priv)
> > > >  					    PCI_SUBVENDOR_ID_REDHAT_QUMRANET &&
> > > >  				    pch->subsystem_device ==
> > > >  					    PCI_SUBDEVICE_ID_QEMU)) {
> > > > +				dev_priv->pch_id = id;
> > > >  				dev_priv->pch_type =
> > > >  					intel_virt_detect_pch(dev_priv);
> > > >  			} else
> > > > -- 
> > > > 2.7.4
> > > > 
> > > _______________________________________________
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> > 
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-- 
Ville Syrjälä
Intel OTC
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