On Fri, Feb 05, 2021 at 12:07:41PM -0800, Navare, Manasi wrote:
On Fri, Feb 05, 2021 at 09:58:07PM +0200, Ville Syrjälä wrote:
On Thu, Feb 04, 2021 at 12:18:40PM +0530, Ankit Nautiyal wrote:
DP-HDMI2.1 PCON has DSC encoder caps defined in registers 0x92-0x9E. Do not read the registers if DPCD rev < 1.4.
Fixes: https://gitlab.freedesktop.org/drm/intel/-/issues/2868 Signed-off-by: Ankit Nautiyal ankit.k.nautiyal@intel.com
drivers/gpu/drm/i915/display/intel_dp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 8c12d5375607..2b83f0f433a2 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -2489,9 +2489,11 @@ static void intel_dp_get_pcon_dsc_cap(struct intel_dp *intel_dp) struct drm_i915_private *i915 = dp_to_i915(intel_dp);
/* Clear the cached register set to avoid using stale values */
- memset(intel_dp->pcon_dsc_dpcd, 0, sizeof(intel_dp->pcon_dsc_dpcd));
- if (intel_dp->dpcd[DP_DPCD_REV] < 0x14)
return;Can't check the spec, but makes sense that this stuff is only valid for recent DCPD revisions.
Acked-by: Ville Syrjälä ville.syrjala@linux.intel.com
Yes checked the DP 1.4 spec and this is correct
I didn't think this is in the DP spec, but rather some special extra spec which I do not have.
Reviewed-by: Manasi Navare manasi.d.navare@intel.com
Manasi
if (drm_dp_dpcd_read(&intel_dp->aux, DP_PCON_DSC_ENCODER, intel_dp->pcon_dsc_dpcd, sizeof(intel_dp->pcon_dsc_dpcd)) < 0) -- 2.29.2
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