From 536faa450e17f32fddb1a2124e3df71a966122cd Mon Sep 17 00:00:00 2001 From: Stanislav Lisovskiy Date: Tue, 30 Jun 2020 05:56:58 +0530 Subject: [PATCH] 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 Signed-off-by: Maarten Lankhorst Link: https://patchwork.freedesktop.org/patch/msgid/20200630002700.5451-2-kunal1.joshi@intel.com --- drivers/gpu/drm/drm_edid.c | 33 +++++++++++++++++++++++++++++++++ include/drm/drm_edid.h | 9 +++++++++ 2 files changed, 42 insertions(+) diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 71ae0cd..920ac9e 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) diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h index 4325431..cfa4f5a 100644 --- a/include/drm/drm_edid.h +++ b/include/drm/drm_edid.h @@ -359,6 +359,15 @@ drm_load_edid_firmware(struct drm_connector *connector) } #endif +/** + * 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 drm_hdmi_avi_infoframe_from_display_mode(struct hdmi_avi_infoframe *frame, const struct drm_connector *connector, -- 2.7.4