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| author |   Ville Syrjälä <ville.syrjala@linux.intel.com> | 2020-03-13 18:20:53 +0200 |
|---|---|---|
| committer | Ville Syrjälä <ville.syrjala@linux.intel.com> | 2020-03-18 17:52:36 +0200 |
| commit | bd1f64df3135ea50827a36dfa3b15d81249e1a37 (patch) | |
| tree | 4b098f7c1d7c5ac95d4665bb69eac29dac0ff779 /drivers/gpu/drm/drm_edid.c | |
| parent | drm/edid: Don't include ext block csum in DispID size (diff) | |
| download | linux-dev-bd1f64df3135ea50827a36dfa3b15d81249e1a37.tar.xz linux-dev-bd1f64df3135ea50827a36dfa3b15d81249e1a37.zip | |
drm/edid: Clarify validate_displayid()
Throw out the magic '5' from validate_displayid() and replace with
the actual thing we mean sizeof(header)+checksum. Also rewrite the
checksum loop to be less hard to parse for mere mortals.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200313162054.16009-9-ville.syrjala@linux.intel.com
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/gpu/drm/drm_edid.c')
| -rw-r--r-- | drivers/gpu/drm/drm_edid.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index d86062d53a67..4cc03bfb5015 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -5097,7 +5097,7 @@ u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edi static int validate_displayid(u8 *displayid, int length, int idx) { - int i; + int i, dispid_length; u8 csum = 0; struct displayid_hdr *base; @@ -5106,15 +5106,18 @@ static int validate_displayid(u8 *displayid, int length, int idx) DRM_DEBUG_KMS("base revision 0x%x, length %d, %d %d\n", base->rev, base->bytes, base->prod_id, base->ext_count); - if (base->bytes + 5 > length - idx) + /* +1 for DispID checksum */ + dispid_length = sizeof(*base) + base->bytes + 1; + if (dispid_length > length - idx) return -EINVAL; - for (i = idx; i <= base->bytes + 5; i++) { - csum += displayid[i]; - } + + 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 0; } |