diff options
Diffstat (limited to 'drivers/gpu/drm/drm_dp_helper.c')
| -rw-r--r-- | drivers/gpu/drm/drm_dp_helper.c | 52 |
1 files changed, 50 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 52e0ca9a5bb1..213fb837e1c4 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -1209,6 +1209,51 @@ int drm_dp_stop_crc(struct drm_dp_aux *aux) } EXPORT_SYMBOL(drm_dp_stop_crc); +struct dpcd_quirk { + u8 oui[3]; + bool is_branch; + u32 quirks; +}; + +#define OUI(first, second, third) { (first), (second), (third) } + +static const struct dpcd_quirk dpcd_quirk_list[] = { + /* Analogix 7737 needs reduced M and N at HBR2 link rates */ + { OUI(0x00, 0x22, 0xb9), true, BIT(DP_DPCD_QUIRK_LIMITED_M_N) }, +}; + +#undef OUI + +/* + * Get a bit mask of DPCD quirks for the sink/branch device identified by + * ident. The quirk data is shared but it's up to the drivers to act on the + * data. + * + * For now, only the OUI (first three bytes) is used, but this may be extended + * to device identification string and hardware/firmware revisions later. + */ +static u32 +drm_dp_get_quirks(const struct drm_dp_dpcd_ident *ident, bool is_branch) +{ + const struct dpcd_quirk *quirk; + u32 quirks = 0; + int i; + + for (i = 0; i < ARRAY_SIZE(dpcd_quirk_list); i++) { + quirk = &dpcd_quirk_list[i]; + + if (quirk->is_branch != is_branch) + continue; + + if (memcmp(quirk->oui, ident->oui, sizeof(ident->oui)) != 0) + continue; + + quirks |= quirk->quirks; + } + + return quirks; +} + /** * drm_dp_read_desc - read sink/branch descriptor from DPCD * @aux: DisplayPort AUX channel @@ -1231,14 +1276,17 @@ int drm_dp_read_desc(struct drm_dp_aux *aux, struct drm_dp_desc *desc, if (ret < 0) return ret; + desc->quirks = drm_dp_get_quirks(ident, is_branch); + dev_id_len = strnlen(ident->device_id, sizeof(ident->device_id)); - DRM_DEBUG_KMS("DP %s: OUI %*phD dev-ID %*pE HW-rev %d.%d SW-rev %d.%d\n", + DRM_DEBUG_KMS("DP %s: OUI %*phD dev-ID %*pE HW-rev %d.%d SW-rev %d.%d quirks 0x%04x\n", is_branch ? "branch" : "sink", (int)sizeof(ident->oui), ident->oui, dev_id_len, ident->device_id, ident->hw_rev >> 4, ident->hw_rev & 0xf, - ident->sw_major_rev, ident->sw_minor_rev); + ident->sw_major_rev, ident->sw_minor_rev, + desc->quirks); return 0; } |