diff options
| author | Eric Anholt <eric@anholt.net> | 2007-09-24 20:23:35 -0700 |
|---|---|---|
| committer | Eric Anholt <eric@anholt.net> | 2007-09-24 20:26:31 -0700 |
| commit | 988f446fe00ac2b92c484a4440613dd82191eadd (patch) | |
| tree | f354ce6f6ff05e8be2f647c4b262999557214c01 | |
| parent | 27ad5d74c20f01516a1bff73be283f8982fcf0fe (diff) | |
[EDID] Ignore reserved bits in deciding monitor vs detailed timing descriptor.
Even though they're defined to zero by the spec, we've seen an EDID block
where the (empty) ASCII strings were stuffed in a byte early, leading to the
descriptor being considered a detailed timing instead.
| -rw-r--r-- | hw/xfree86/ddc/edid.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/hw/xfree86/ddc/edid.h b/hw/xfree86/ddc/edid.h index 0b6a15af0..4487273cd 100644 --- a/hw/xfree86/ddc/edid.h +++ b/hw/xfree86/ddc/edid.h @@ -190,7 +190,14 @@ /* EDID Ver. >= 1.2 */ -#define _IS_MONITOR_DESC(x) (x[0] == 0 && x[1] == 0 && x[2] == 0 && x[4] == 0) +/** + * Returns true if the pointer is the start of a monitor descriptor block + * instead of a detailed timing descriptor. + * + * Checking the reserved pad fields for zeroes fails on some monitors with + * broken empty ASCII strings. Only the first two bytes are reliable. + */ +#define _IS_MONITOR_DESC(x) (x[0] == 0 && x[1] == 0) #define IS_MONITOR_DESC _IS_MONITOR_DESC(c) #define _PIXEL_CLOCK(x) (x[0] + (x[1] << 8)) * 10000 #define PIXEL_CLOCK _PIXEL_CLOCK(c) |