[Intel-gfx] [PATCH v2 5/8] drm/i915/lspcon: Fail LSPCON probe if the start of DPCD can't be read

[Imre Deak]

All types of DP devices (eDP, DP sink, DP branch) will fail their probe
if the start of DPCD can't be read. The LSPCON PCON functionality also
depends on accessing this area, so fail the probe if the read fails.

Cc: Shashank Sharma <shashank.sharma at intel.com>
Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c     | 2 +-
 drivers/gpu/drm/i915/intel_drv.h    | 2 ++
 drivers/gpu/drm/i915/intel_lspcon.c | 5 +++++
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 726fdf2..62c5512 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3495,7 +3495,7 @@ intel_dp_link_down(struct intel_dp *intel_dp)
 	intel_dp->DP = DP;
 }
 
-static bool
+bool
 intel_dp_read_dpcd(struct intel_dp *intel_dp)
 {
 	if (drm_dp_dpcd_read(&intel_dp->aux, 0x000, intel_dp->dpcd,
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 4c9f953..ff9d2dc 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1461,6 +1461,8 @@ static inline unsigned int intel_dp_unused_lane_mask(int lane_count)
 	return ~((1 << lane_count) - 1) & 0xf;
 }
 
+bool intel_dp_read_dpcd(struct intel_dp *intel_dp);
+
 /* intel_dp_aux_backlight.c */
 int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector);
 
diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
index 632149c..23b817a 100644
--- a/drivers/gpu/drm/i915/intel_lspcon.c
+++ b/drivers/gpu/drm/i915/intel_lspcon.c
@@ -131,6 +131,11 @@ bool lspcon_init(struct intel_digital_port *intel_dig_port)
 		}
 	}
 
+	if (!intel_dp_read_dpcd(dp)) {
+		DRM_ERROR("LSPCON DPCD read failed\n");
+		return false;
+	}
+
 	DRM_DEBUG_KMS("Success: LSPCON init\n");
 	return true;
 }
-- 
2.5.0