Commit 051963d4 authored by Thomas Reim's avatar Thomas Reim Committed by Dave Airlie

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: <stable@kernel.org>
Signed-off-by: default avatarThomas Reim <reimth@gmail.com>
Reviewed-by: default avatarAlex Deucher <alexdeucher@gmail.com>
Acked-by: default avatarStephen Michaels <Stephen.Micheals@gmail.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 5037f8ac
...@@ -127,6 +127,23 @@ static const u8 edid_header[] = { ...@@ -127,6 +127,23 @@ static const u8 edid_header[] = {
0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00 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 * Sanity check the EDID block (base or extension). Return 0 if the block
* doesn't check out, or 1 if it's valid. * doesn't check out, or 1 if it's valid.
...@@ -139,12 +156,7 @@ drm_edid_block_valid(u8 *raw_edid) ...@@ -139,12 +156,7 @@ drm_edid_block_valid(u8 *raw_edid)
struct edid *edid = (struct edid *)raw_edid; struct edid *edid = (struct edid *)raw_edid;
if (raw_edid[0] == 0x00) { if (raw_edid[0] == 0x00) {
int score = 0; int score = drm_edid_header_is_valid(raw_edid);
for (i = 0; i < sizeof(edid_header); i++)
if (raw_edid[i] == edid_header[i])
score++;
if (score == 8) ; if (score == 8) ;
else if (score >= 6) { else if (score >= 6) {
DRM_DEBUG("Fixing EDID header, your hardware may be failing\n"); DRM_DEBUG("Fixing EDID header, your hardware may be failing\n");
......
...@@ -804,6 +804,7 @@ extern struct drm_display_mode *drm_gtf_mode_complex(struct drm_device *dev, ...@@ -804,6 +804,7 @@ extern struct drm_display_mode *drm_gtf_mode_complex(struct drm_device *dev,
extern int drm_add_modes_noedid(struct drm_connector *connector, extern int drm_add_modes_noedid(struct drm_connector *connector,
int hdisplay, int vdisplay); int hdisplay, int vdisplay);
extern int drm_edid_header_is_valid(const u8 *raw_edid);
extern bool drm_edid_is_valid(struct edid *edid); extern bool drm_edid_is_valid(struct edid *edid);
struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev, struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,
int hsize, int vsize, int fresh); int hsize, int vsize, int fresh);
......
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