drm/edid: Try harder to fix up base EDID blocks

Requiring the first byte of the EDID base block header to be 0 means we
don't fix up as many transfer errors as we could.  Instead have the
callers specify whether it's meant to be block 0 or not, and
conditionally run header fixup based on that.

Bugzilla: https://bugzilla.redhat.com/812890
Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Alex Deucher <alexdeucher@gmail.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index c6366e9..f425379 100644 (file)
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -149,13 +149,13 @@ EXPORT_SYMBOL(drm_edid_header_is_valid);
  * Sanity check the EDID block (base or extension).  Return 0 if the block
  * doesn't check out, or 1 if it's valid.
  */
-bool drm_edid_block_valid(u8 *raw_edid)
+bool drm_edid_block_valid(u8 *raw_edid, int block)
 {
        int i;
        u8 csum = 0;
        struct edid *edid = (struct edid *)raw_edid;
 
-       if (raw_edid[0] == 0x00) {
+       if (block == 0) {
                int score = drm_edid_header_is_valid(raw_edid);
                if (score == 8) ;
                else if (score >= 6) {
@@ -219,7 +219,7 @@ bool drm_edid_is_valid(struct edid *edid)
                return false;
 
        for (i = 0; i <= edid->extensions; i++)
-               if (!drm_edid_block_valid(raw + i * EDID_LENGTH))
+               if (!drm_edid_block_valid(raw + i * EDID_LENGTH, i))
                        return false;
 
        return true;
@@ -299,7 +299,7 @@ drm_do_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter)
        for (i = 0; i < 4; i++) {
                if (drm_do_probe_ddc_edid(adapter, block, 0, EDID_LENGTH))
                        goto out;
-               if (drm_edid_block_valid(block))
+               if (drm_edid_block_valid(block, 0))
                        break;
                if (i == 0 && drm_edid_is_zero(block, EDID_LENGTH)) {
                        connector->null_edid_counter++;
@@ -324,7 +324,7 @@ drm_do_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter)
                                  block + (valid_extensions + 1) * EDID_LENGTH,
                                  j, EDID_LENGTH))
                                goto out;
-                       if (drm_edid_block_valid(block + (valid_extensions + 1) * EDID_LENGTH)) {
+                       if (drm_edid_block_valid(block + (valid_extensions + 1) * EDID_LENGTH, j)) {
                                valid_extensions++;
                                break;
                        }

diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 6f5faf6..f35e7ed 100644 (file)
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1012,7 +1012,7 @@ extern int drm_add_modes_noedid(struct drm_connector *connector,
                                int hdisplay, int vdisplay);
 
 extern int drm_edid_header_is_valid(const u8 *raw_edid);
-extern bool drm_edid_block_valid(u8 *raw_edid);
+extern bool drm_edid_block_valid(u8 *raw_edid, int block);
 extern bool drm_edid_is_valid(struct edid *edid);
 struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,
                                           int hsize, int vsize, int fresh,