3 files changed, 38 insertions, 19 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 421b7e2ece3b..8d9e7c0e9e4b 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8091,6 +8091,9 @@ intel_pipe_config_compare(struct drm_device *dev,
                 return false; \
         }
 
+#define PIPE_CONF_QUIRK(quirk)  \
+        ((current_config->quirks | pipe_config->quirks) & (quirk))
+
         PIPE_CONF_CHECK_I(cpu_transcoder);
 
         PIPE_CONF_CHECK_I(has_pch_encoder);
@@ -8121,14 +8124,16 @@ intel_pipe_config_compare(struct drm_device *dev,
         PIPE_CONF_CHECK_FLAGS(adjusted_mode.flags,
                               DRM_MODE_FLAG_INTERLACE);
 
-        PIPE_CONF_CHECK_FLAGS(adjusted_mode.flags,
-                              DRM_MODE_FLAG_PHSYNC);
-        PIPE_CONF_CHECK_FLAGS(adjusted_mode.flags,
-                              DRM_MODE_FLAG_NHSYNC);
-        PIPE_CONF_CHECK_FLAGS(adjusted_mode.flags,
-                              DRM_MODE_FLAG_PVSYNC);
-        PIPE_CONF_CHECK_FLAGS(adjusted_mode.flags,
-                              DRM_MODE_FLAG_NVSYNC);
+        if (!PIPE_CONF_QUIRK(PIPE_CONFIG_QUIRK_MODE_SYNC_FLAGS)) {
+                PIPE_CONF_CHECK_FLAGS(adjusted_mode.flags,
+                                      DRM_MODE_FLAG_PHSYNC);
+                PIPE_CONF_CHECK_FLAGS(adjusted_mode.flags,
+                                      DRM_MODE_FLAG_NHSYNC);
+                PIPE_CONF_CHECK_FLAGS(adjusted_mode.flags,
+                                      DRM_MODE_FLAG_PVSYNC);
+                PIPE_CONF_CHECK_FLAGS(adjusted_mode.flags,
+                                      DRM_MODE_FLAG_NVSYNC);
+        }
 
         PIPE_CONF_CHECK_I(requested_mode.hdisplay);
         PIPE_CONF_CHECK_I(requested_mode.vdisplay);
@@ -8145,6 +8150,7 @@ intel_pipe_config_compare(struct drm_device *dev,
 
 #undef PIPE_CONF_CHECK_I
 #undef PIPE_CONF_CHECK_FLAGS
+#undef PIPE_CONF_QUIRK
 
         return true;
 }
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 1735cdc86770..b76a956cfb9a 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -193,6 +193,17 @@ typedef struct dpll {
 } intel_clock_t;
 
 struct intel_crtc_config {
+        /**
+         * quirks - bitfield with hw state readout quirks
+         *
+         * For various reasons the hw state readout code might not be able to
+         * completely faithfully read out the current state. These cases are
+         * tracked with quirk flags so that fastboot and state checker can act
+         * accordingly.
+         */
+#define PIPE_CONFIG_QUIRK_MODE_SYNC_FLAGS (1<<0) /* unreliable sync mode.flags */
+        unsigned long quirks;
+
         struct drm_display_mode requested_mode;
         struct drm_display_mode adjusted_mode;
         /* This flag must be set by the encoder's compute_config callback if it
diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 5c816dd75bec..960358d8e336 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -1324,19 +1324,21 @@ static void intel_sdvo_get_config(struct intel_encoder *encoder,
 
         ret = intel_sdvo_get_input_timing(intel_sdvo, &dtd);
         if (!ret) {
+                /* Some sdvo encoders are not spec compliant and don't
+                 * implement the mandatory get_timings function. */
                 DRM_DEBUG_DRIVER("failed to retrieve SDVO DTD\n");
-                return;
-        }
-
-        if (dtd.part2.dtd_flags & DTD_FLAG_HSYNC_POSITIVE)
-                flags |= DRM_MODE_FLAG_PHSYNC;
-        else
-                flags |= DRM_MODE_FLAG_NHSYNC;
+                pipe_config->quirks |= PIPE_CONFIG_QUIRK_MODE_SYNC_FLAGS;
+        } else {
+                if (dtd.part2.dtd_flags & DTD_FLAG_HSYNC_POSITIVE)
+                        flags |= DRM_MODE_FLAG_PHSYNC;
+                else
+                        flags |= DRM_MODE_FLAG_NHSYNC;
 
-        if (dtd.part2.dtd_flags & DTD_FLAG_VSYNC_POSITIVE)
-                flags |= DRM_MODE_FLAG_PVSYNC;
-        else
-                flags |= DRM_MODE_FLAG_NVSYNC;
+                if (dtd.part2.dtd_flags & DTD_FLAG_VSYNC_POSITIVE)
+                        flags |= DRM_MODE_FLAG_PVSYNC;
+                else
+                        flags |= DRM_MODE_FLAG_NVSYNC;
+        }
 
         pipe_config->adjusted_mode.flags |= flags;