drm/radeon/kms: fix extended lvds info parsing

On rev <= 1.1 tables, the offset is absolute,
on newer tables, it's relative.

Fixes:
https://bugzilla.redhat.com/show_bug.cgi?id=700326

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 11 insertions, 3 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c
index dd881d035f09..90dfb2b8cf03 100644
--- a/drivers/gpu/drm/radeon/radeon_atombios.c
+++ b/drivers/gpu/drm/radeon/radeon_atombios.c
@@ -1574,9 +1574,17 @@ struct radeon_encoder_atom_dig *radeon_atombios_get_lvds_info(struct
                         ATOM_FAKE_EDID_PATCH_RECORD *fake_edid_record;
                         ATOM_PANEL_RESOLUTION_PATCH_RECORD *panel_res_record;
                         bool bad_record = false;
-                        u8 *record = (u8 *)(mode_info->atom_context->bios +
-                                            data_offset +
-                                            le16_to_cpu(lvds_info->info.usModePatchTableOffset));
+                        u8 *record;
+
+                        if ((frev == 1) && (crev < 2))
+                                /* absolute */
+                                record = (u8 *)(mode_info->atom_context->bios +
+                                                le16_to_cpu(lvds_info->info.usModePatchTableOffset));
+                        else
+                                /* relative */
+                                record = (u8 *)(mode_info->atom_context->bios +
+                                                data_offset +
+                                                le16_to_cpu(lvds_info->info.usModePatchTableOffset));
                         while (*record != ATOM_RECORD_END_TYPE) {
                                 switch (*record) {
                                 case LCD_MODE_PATCH_RECORD_MODE_TYPE: