drm/radeon/kms/combios: verify dac_adj values are valid
Some vbios dac_adj tables are all zeros. Check for that
case and use the default table if so.
Should fix fdo bug 27478.
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_combios.c b/drivers/gpu/drm/radeon/radeon_combios.c
index 2becded..37db8ad 100644
--- a/drivers/gpu/drm/radeon/radeon_combios.c
+++ b/drivers/gpu/drm/radeon/radeon_combios.c
@@ -760,7 +760,9 @@
dac = RBIOS8(dac_info + 0x3) & 0xf;
p_dac->ps2_pdac_adj = (bg << 8) | (dac);
}
- found = 1;
+ /* if the values are all zeros, use the table */
+ if (p_dac->ps2_pdac_adj)
+ found = 1;
}
if (!found) /* fallback to defaults */
@@ -895,7 +897,9 @@
bg = RBIOS8(dac_info + 0x10) & 0xf;
dac = RBIOS8(dac_info + 0x11) & 0xf;
tv_dac->ntsc_tvdac_adj = (bg << 16) | (dac << 20);
- found = 1;
+ /* if the values are all zeros, use the table */
+ if (tv_dac->ps2_tvdac_adj)
+ found = 1;
} else if (rev > 1) {
bg = RBIOS8(dac_info + 0xc) & 0xf;
dac = (RBIOS8(dac_info + 0xc) >> 4) & 0xf;
@@ -908,7 +912,9 @@
bg = RBIOS8(dac_info + 0xe) & 0xf;
dac = (RBIOS8(dac_info + 0xe) >> 4) & 0xf;
tv_dac->ntsc_tvdac_adj = (bg << 16) | (dac << 20);
- found = 1;
+ /* if the values are all zeros, use the table */
+ if (tv_dac->ps2_tvdac_adj)
+ found = 1;
}
tv_dac->tv_std = radeon_combios_get_tv_info(rdev);
}
@@ -925,7 +931,9 @@
(bg << 16) | (dac << 20);
tv_dac->pal_tvdac_adj = tv_dac->ps2_tvdac_adj;
tv_dac->ntsc_tvdac_adj = tv_dac->ps2_tvdac_adj;
- found = 1;
+ /* if the values are all zeros, use the table */
+ if (tv_dac->ps2_tvdac_adj)
+ found = 1;
} else {
bg = RBIOS8(dac_info + 0x4) & 0xf;
dac = RBIOS8(dac_info + 0x5) & 0xf;
@@ -933,7 +941,9 @@
(bg << 16) | (dac << 20);
tv_dac->pal_tvdac_adj = tv_dac->ps2_tvdac_adj;
tv_dac->ntsc_tvdac_adj = tv_dac->ps2_tvdac_adj;
- found = 1;
+ /* if the values are all zeros, use the table */
+ if (tv_dac->ps2_tvdac_adj)
+ found = 1;
}
} else {
DRM_INFO("No TV DAC info found in BIOS\n");