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drm/displayid: return struct displayid_header from validate_displayid() 

Avoid figuring out the header pointer multiple times.

Cc: Iaroslav Boliukin <iam@lach.pw>
Cc: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/e840c744d165608a41db5a5e2bd4b0205783c697.1676580180.git.jani.nikula@intel.com
This commit is contained in:
Jani Nikula 2023-02-16 22:44:59 +02:00 committed by Dmitry Osipenko
parent 5bacecc3c5
commit 5631f6a043
1 changed files with 8 additions and 9 deletions
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17
drivers/gpu/drm/drm_displayid.c
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@ -20,7 +20,8 @@ displayid_get_header(const u8 *displayid, int length, int index)
return base;
}
static int validate_displayid(const u8 *displayid, int length, int idx)
static const struct displayid_header *
validate_displayid(const u8 *displayid, int length, int idx)
{
int i, dispid_length;
u8 csum = 0;
@ -28,7 +29,7 @@ static int validate_displayid(const u8 *displayid, int length, int idx)
base = displayid_get_header(displayid, length, idx);
if (IS_ERR(base))
return PTR_ERR(base);
return base;
DRM_DEBUG_KMS("base revision 0x%x, length %d, %d %d\n",
base->rev, base->bytes, base->prod_id, base->ext_count);
@ -36,16 +37,16 @@ static int validate_displayid(const u8 *displayid, int length, int idx)
/* +1 for DispID checksum */
dispid_length = sizeof(*base) + base->bytes + 1;
if (dispid_length > length - idx)
return -EINVAL;
return ERR_PTR(-EINVAL);
for (i = 0; i < dispid_length; i++)
csum += displayid[idx + i];
if (csum) {
DRM_NOTE("DisplayID checksum invalid, remainder is %d\n", csum);
return -EINVAL;
return ERR_PTR(-EINVAL);
}
return 0;
return base;
}
static const u8 *drm_find_displayid_extension(const struct drm_edid *drm_edid,
@ -54,7 +55,6 @@ static const u8 *drm_find_displayid_extension(const struct drm_edid *drm_edid,
{
const u8 *displayid = drm_find_edid_extension(drm_edid, DISPLAYID_EXT, ext_index);
const struct displayid_header *base;
int ret;
if (!displayid)
return NULL;
@ -63,11 +63,10 @@ static const u8 *drm_find_displayid_extension(const struct drm_edid *drm_edid,
*length = EDID_LENGTH - 1;
*idx = 1;
ret = validate_displayid(displayid, *length, *idx);
if (ret)
base = validate_displayid(displayid, *length, *idx);
if (IS_ERR(base))
return NULL;
base = (const struct displayid_header *)&displayid[*idx];
*length = *idx + sizeof(*base) + base->bytes;
return displayid;