drm/i915: Read DP branch device HW revision
HW revision is mandatory field for DisplayPort branch
devices. This is defined in DPCD register field 0x509.
v2: move drm_dp_ds_revision structure to be part of
drm_dp_link structure (Daniel)
v3: remove dependency to drm_dp_helper but instead parse
DPCD and print HW revision info to dmesg (Ville)
Reviewed-by: Jim Bride <jim.bride@linux.intel.com>
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1473419458-17080-8-git-send-email-mika.kahola@intel.com
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index c69ad13..bb0417c 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1419,6 +1419,25 @@
DRM_DEBUG_KMS("common rates: %s\n", str);
}
+static void intel_dp_print_hw_revision(struct intel_dp *intel_dp)
+{
+ uint8_t rev;
+ int len;
+
+ if ((drm_debug & DRM_UT_KMS) == 0)
+ return;
+
+ if (!(intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] &
+ DP_DWN_STRM_PORT_PRESENT))
+ return;
+
+ len = drm_dp_dpcd_read(&intel_dp->aux, DP_BRANCH_HW_REV, &rev, 1);
+ if (len < 0)
+ return;
+
+ DRM_DEBUG_KMS("sink hw revision: %d.%d\n", (rev & 0xf0) >> 4, rev & 0xf);
+}
+
static int rate_to_index(int find, const int *rates)
{
int i = 0;
@@ -4312,6 +4331,8 @@
intel_dp_probe_oui(intel_dp);
+ intel_dp_print_hw_revision(intel_dp);
+
intel_dp_configure_mst(intel_dp);
if (intel_dp->is_mst) {