[ 16/23] drm/radeon: improve dac adjust heuristics for legacy pdac

Greg Kroah-Hartman
2013-08-02T10:23:22Z

From: Alex Deucher <alexander.deucher@amd.com>

commit 03ed8cf9b28d886c64c7e705c7bb1a365fd8fb95 upstream.

Hopefully avoid more quirks in the future due to bogus
vbios dac data.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/radeon/radeon_combios.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/radeon/radeon_combios.c
+++ b/drivers/gpu/drm/radeon/radeon_combios.c
@@ -890,8 +890,10 @@ struct radeon_encoder_primary_dac *radeo
dac = RBIOS8(dac_info + 0x3) & 0xf;
p_dac->ps2_pdac_adj = (bg << 8) | (dac);
}
- /* if the values are all zeros, use the table */
- if (p_dac->ps2_pdac_adj)
+ /* if the values are zeros, use the table */
+ if ((dac == 0) || (bg == 0))
+ found = 0;
+ else
found = 1;
}