From 051963d4832ed61e5ae74f5330b0a94489e101b9 Mon Sep 17 00:00:00 2001 From: Thomas Reim Date: Fri, 29 Jul 2011 14:28:57 +0000 Subject: drm: Separate EDID Header Check from EDID Block Check Provides function drm_edid_header_is_valid() for EDID header check and replaces EDID header check part of function drm_edid_block_valid() by a call of drm_edid_header_is_valid(). This is a prerequisite to extend DDC probing, e. g. in function radeon_ddc_probe() for Radeon devices, by a central EDID header check. Tested for kernel 2.6.35, 2.6.38 and 3.0 Cc: Signed-off-by: Thomas Reim Reviewed-by: Alex Deucher Acked-by: Stephen Michaels Signed-off-by: Dave Airlie --- drivers/gpu/drm/drm_edid.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) (limited to 'drivers/gpu') diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 7496d24..7425e5c 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -127,6 +127,23 @@ static const u8 edid_header[] = { 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00 }; + /* + * Sanity check the header of the base EDID block. Return 8 if the header + * is perfect, down to 0 if it's totally wrong. + */ +int drm_edid_header_is_valid(const u8 *raw_edid) +{ + int i, score = 0; + + for (i = 0; i < sizeof(edid_header); i++) + if (raw_edid[i] == edid_header[i]) + score++; + + return score; +} +EXPORT_SYMBOL(drm_edid_header_is_valid); + + /* * Sanity check the EDID block (base or extension). Return 0 if the block * doesn't check out, or 1 if it's valid. @@ -139,12 +156,7 @@ drm_edid_block_valid(u8 *raw_edid) struct edid *edid = (struct edid *)raw_edid; if (raw_edid[0] == 0x00) { - int score = 0; - - for (i = 0; i < sizeof(edid_header); i++) - if (raw_edid[i] == edid_header[i]) - score++; - + int score = drm_edid_header_is_valid(raw_edid); if (score == 8) ; else if (score >= 6) { DRM_DEBUG("Fixing EDID header, your hardware may be failing\n"); -- cgit v1.1