From: Tomeu Vizoso Date: Thu, 8 Dec 2016 13:11:56 +0000 (+0100) Subject: drm/edid: Don't print an error if the checksum of a CEA block is wrong X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=82d753567f6f3bb5059bd18e8fd8aa7915fcbe05;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git drm/edid: Don't print an error if the checksum of a CEA block is wrong It's common to share screens within CI labs, and it's also common for KVM switches to alter the contents of the CEA block but leave the checksum outdated. So in this case, print a debug message instead of an error. References: https://bugs.freedesktop.org/show_bug.cgi?id=98228 Cc: Chris Wilson Cc: Tomi Sarvela Cc: intel-gfx@lists.freedesktop.org Signed-off-by: Tomeu Vizoso Tested-by: Jari Tahvanainen Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/1481202716-31317-1-git-send-email-tomeu.vizoso@collabora.com --- diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index c8baab9bee0d..5a3b34a88ac3 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -1131,16 +1131,19 @@ bool drm_edid_block_valid(u8 *raw_edid, int block, bool print_bad_edid, csum = drm_edid_block_checksum(raw_edid); if (csum) { - if (print_bad_edid) { - DRM_ERROR("EDID checksum is invalid, remainder is %d\n", csum); - } - if (edid_corrupt) *edid_corrupt = true; /* allow CEA to slide through, switches mangle this */ - if (raw_edid[0] != 0x02) + if (raw_edid[0] == CEA_EXT) { + DRM_DEBUG("EDID checksum is invalid, remainder is %d\n", csum); + DRM_DEBUG("Assuming a KVM switch modified the CEA block but left the original checksum\n"); + } else { + if (print_bad_edid) + DRM_ERROR("EDID checksum is invalid, remainder is %d\n", csum); + goto bad; + } } /* per-block-type checks */