Docs/EDID: Fixed erroneous bits of XOFFSET, XPULSE, YOFFSET and YPULSE
The problem was found when EDID data sets for displays other
than the provided samples were generated. The patch has
no effect on the provided samples that still match the data
used in drivers/gpu/drm/drm_edid_load.c.
The provided samples use small values for XOFFSET, XPULSE,
YOFFSET and YPULSE, where the error doesn't occur. This fix
corrects the use of that values in case of high values, because
the most significant bits were treated incorrectly.
So in edid.S msbs4 should use bit 8 and 9 of XOFFSET and XPULS.
For YOFFSET and YPULSE msbs4 should use bit 4 and 5.
lsbs2 was introduced for a better overview, without
functional change.
Removing also the useless value 63 of all files, because
it is added in the *.S description files and then it is
subtracted in edid.S.
Signed-off-by: Christoph Niedermaier <cniedermaier@dh-electronics.de>
Reviewed-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/EDID/edid.S b/Documentation/EDID/edid.S
index ef082dc..c3d1381 100644
--- a/Documentation/EDID/edid.S
+++ b/Documentation/EDID/edid.S
@@ -47,9 +47,11 @@
#define mfgname2id(v1,v2,v3) \
((((v1-'@')&0x1f)<<10)+(((v2-'@')&0x1f)<<5)+((v3-'@')&0x1f))
#define swap16(v1) ((v1>>8)+((v1&0xff)<<8))
+#define lsbs2(v1,v2) (((v1&0x0f)<<4)+(v2&0x0f))
#define msbs2(v1,v2) ((((v1>>8)&0x0f)<<4)+((v2>>8)&0x0f))
#define msbs4(v1,v2,v3,v4) \
- (((v1&0x03)>>2)+((v2&0x03)>>4)+((v3&0x03)>>6)+((v4&0x03)>>8))
+ ((((v1>>8)&0x03)<<6)+(((v2>>8)&0x03)<<4)+\
+ (((v3>>4)&0x03)<<2)+((v4>>4)&0x03))
#define pixdpi2mm(pix,dpi) ((pix*25)/dpi)
#define xsize pixdpi2mm(XPIX,DPI)
#define ysize pixdpi2mm(YPIX,DPI)
@@ -200,9 +202,9 @@
x_snc_off_lsb: .byte XOFFSET&0xff
/* Horizontal sync pulse width pixels 8 lsbits (0-1023) */
x_snc_pls_lsb: .byte XPULSE&0xff
-/* Bits 7-4 Vertical sync offset lines 4 lsbits -63)
- Bits 3-0 Vertical sync pulse width lines 4 lsbits -63) */
-y_snc_lsb: .byte ((YOFFSET-63)<<4)+(YPULSE-63)
+/* Bits 7-4 Vertical sync offset lines 4 lsbits (0-63)
+ Bits 3-0 Vertical sync pulse width lines 4 lsbits (0-63) */
+y_snc_lsb: .byte lsbs2(YOFFSET, YPULSE)
/* Bits 7-6 Horizontal sync offset pixels 2 msbits
Bits 5-4 Horizontal sync pulse width pixels 2 msbits
Bits 3-2 Vertical sync offset lines 2 msbits