diff options
Diffstat (limited to 'drivers/gpu/drm/drm_displayid.c')
-rw-r--r-- | drivers/gpu/drm/drm_displayid.c | 62 |
1 files changed, 53 insertions, 9 deletions
diff --git a/drivers/gpu/drm/drm_displayid.c b/drivers/gpu/drm/drm_displayid.c index 38ea8203df45..9edc111be7ee 100644 --- a/drivers/gpu/drm/drm_displayid.c +++ b/drivers/gpu/drm/drm_displayid.c @@ -7,13 +7,29 @@ #include <drm/drm_edid.h> #include <drm/drm_print.h> -static int validate_displayid(const u8 *displayid, int length, int idx) +static const struct displayid_header * +displayid_get_header(const u8 *displayid, int length, int index) +{ + const struct displayid_header *base; + + if (sizeof(*base) > length - index) + return ERR_PTR(-EINVAL); + + base = (const struct displayid_header *)&displayid[index]; + + return base; +} + +static const struct displayid_header * +validate_displayid(const u8 *displayid, int length, int idx) { int i, dispid_length; u8 csum = 0; const struct displayid_header *base; - base = (const struct displayid_header *)&displayid[idx]; + base = displayid_get_header(displayid, length, idx); + if (IS_ERR(base)) + return base; DRM_DEBUG_KMS("base revision 0x%x, length %d, %d %d\n", base->rev, base->bytes, base->prod_id, base->ext_count); @@ -21,16 +37,16 @@ static int validate_displayid(const u8 *displayid, int length, int idx) /* +1 for DispID checksum */ dispid_length = sizeof(*base) + base->bytes + 1; if (dispid_length > length - idx) - return -EINVAL; + return ERR_PTR(-EINVAL); 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 ERR_PTR(-EINVAL); } - return 0; + return base; } static const u8 *drm_find_displayid_extension(const struct drm_edid *drm_edid, @@ -39,7 +55,6 @@ static const u8 *drm_find_displayid_extension(const struct drm_edid *drm_edid, { const u8 *displayid = drm_find_edid_extension(drm_edid, DISPLAYID_EXT, ext_index); const struct displayid_header *base; - int ret; if (!displayid) return NULL; @@ -48,11 +63,10 @@ static const u8 *drm_find_displayid_extension(const struct drm_edid *drm_edid, *length = EDID_LENGTH - 1; *idx = 1; - ret = validate_displayid(displayid, *length, *idx); - if (ret) + base = validate_displayid(displayid, *length, *idx); + if (IS_ERR(base)) return NULL; - base = (const struct displayid_header *)&displayid[*idx]; *length = *idx + sizeof(*base) + base->bytes; return displayid; @@ -109,6 +123,9 @@ __displayid_iter_next(struct displayid_iter *iter) } for (;;) { + /* The first section we encounter is the base section */ + bool base_section = !iter->section; + iter->section = drm_find_displayid_extension(iter->drm_edid, &iter->length, &iter->idx, @@ -118,6 +135,18 @@ __displayid_iter_next(struct displayid_iter *iter) return NULL; } + /* Save the structure version and primary use case. */ + if (base_section) { + const struct displayid_header *base; + + base = displayid_get_header(iter->section, iter->length, + iter->idx); + if (!IS_ERR(base)) { + iter->version = base->rev; + iter->primary_use = base->prod_id; + } + } + iter->idx += sizeof(struct displayid_header); block = displayid_iter_block(iter); @@ -130,3 +159,18 @@ void displayid_iter_end(struct displayid_iter *iter) { memset(iter, 0, sizeof(*iter)); } + +/* DisplayID Structure Version/Revision from the Base Section. */ +u8 displayid_version(const struct displayid_iter *iter) +{ + return iter->version; +} + +/* + * DisplayID Primary Use Case (2.0+) or Product Type Identifier (1.0-1.3) from + * the Base Section. + */ +u8 displayid_primary_use(const struct displayid_iter *iter) +{ + return iter->primary_use; +} |