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| author | Stanislav Lisovskiy <stanislav.lisovskiy@intel.com> | 2020-06-30 05:56:58 +0530 |
|---|---|---|
| committer | Maarten Lankhorst <maarten.lankhorst@linux.intel.com> | 2020-06-30 13:31:15 +0200 |
| commit | 536faa450e17f32fddb1a2124e3df71a966122cd (patch) | |
| tree | d7c36abd6fa032fc21dc6f044b20295176001a2b /drivers/gpu/drm/drm_edid.c | |
| parent | e9d636ab77ea2d1beeaf2bbb881331318ea5a6eb (diff) | |
| download | lwn-536faa450e17f32fddb1a2124e3df71a966122cd.tar.gz lwn-536faa450e17f32fddb1a2124e3df71a966122cd.zip | |
drm: Add helper to compare edids.
Many drivers would benefit from using
drm helper to compare edid, rather
than bothering with own implementation.
v2: Added documentation for this function.
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200630002700.5451-2-kunal1.joshi@intel.com
Diffstat (limited to 'drivers/gpu/drm/drm_edid.c')
| -rw-r--r-- | drivers/gpu/drm/drm_edid.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 71ae0cd6d576..920ac9ef6018 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -1616,6 +1616,39 @@ static bool drm_edid_is_zero(const u8 *in_edid, int length) } /** + * drm_edid_are_equal - compare two edid blobs. + * @edid1: pointer to first blob + * @edid2: pointer to second blob + * This helper can be used during probing to determine if + * edid had changed. + */ +bool drm_edid_are_equal(const struct edid *edid1, const struct edid *edid2) +{ + int edid1_len, edid2_len; + bool edid1_present = edid1 != NULL; + bool edid2_present = edid2 != NULL; + + if (edid1_present != edid2_present) + return false; + + if (edid1) { + + edid1_len = EDID_LENGTH * (1 + edid1->extensions); + edid2_len = EDID_LENGTH * (1 + edid2->extensions); + + if (edid1_len != edid2_len) + return false; + + if (memcmp(edid1, edid2, edid1_len)) + return false; + } + + return true; +} +EXPORT_SYMBOL(drm_edid_are_equal); + + +/** * drm_edid_block_valid - Sanity check the EDID block (base or extension) * @raw_edid: pointer to raw EDID block * @block: type of block to validate (0 for base, extension otherwise) |