jcs.org
jcs's openbsd hax
openbsd
drm/displayid: add quirk to ignore DisplayID checksum errors
From Jani Nikula
f548c5ebe656506e81a8145798ff194d57d00a3c in linux-6.12.y/6.12.64
83cbb4d33dc22b0ca1a4e85c6e892c9b729e28d4 in mainline linux
+39
-4
+37
-4
sys/dev/pci/drm/drm_displayid.c
+37
-4
sys/dev/pci/drm/drm_displayid.c
···
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#include "drm_crtc_internal.h"
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#include "drm_displayid_internal.h"
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enum {
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QUIRK_IGNORE_CHECKSUM,
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};
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struct displayid_quirk {
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const struct drm_edid_ident ident;
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u8 quirks;
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};
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static const struct displayid_quirk quirks[] = {
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{
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.ident = DRM_EDID_IDENT_INIT('C', 'S', 'O', 5142, "MNE007ZA1-5"),
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.quirks = BIT(QUIRK_IGNORE_CHECKSUM),
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},
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};
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static u8 get_quirks(const struct drm_edid *drm_edid)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(quirks); i++) {
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if (drm_edid_match(drm_edid, &quirks[i].ident))
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return quirks[i].quirks;
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}
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return 0;
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}
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static const struct displayid_header *
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displayid_get_header(const u8 *displayid, int length, int index)
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{
···
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}
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static const struct displayid_header *
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validate_displayid(const u8 *displayid, int length, int idx)
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validate_displayid(const u8 *displayid, int length, int idx, bool ignore_checksum)
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{
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int i, dispid_length;
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u8 csum = 0;
···
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for (i = 0; i < dispid_length; i++)
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csum += displayid[idx + i];
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if (csum) {
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DRM_NOTE("DisplayID checksum invalid, remainder is %d\n", csum);
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return ERR_PTR(-EINVAL);
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DRM_NOTE("DisplayID checksum invalid, remainder is %d%s\n", csum,
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ignore_checksum ? " (ignoring)" : "");
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if (!ignore_checksum)
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return ERR_PTR(-EINVAL);
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}
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return base;
···
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{
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const struct displayid_header *base;
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const u8 *displayid;
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bool ignore_checksum = iter->quirks & BIT(QUIRK_IGNORE_CHECKSUM);
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displayid = drm_edid_find_extension(iter->drm_edid, DISPLAYID_EXT, &iter->ext_index);
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if (!displayid)
···
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iter->length = EDID_LENGTH - 1;
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iter->idx = 1;
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base = validate_displayid(displayid, iter->length, iter->idx);
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base = validate_displayid(displayid, iter->length, iter->idx, ignore_checksum);
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if (IS_ERR(base))
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return NULL;
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···
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memset(iter, 0, sizeof(*iter));
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iter->drm_edid = drm_edid;
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iter->quirks = get_quirks(drm_edid);
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}
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static const struct displayid_block *