diff options
| -rw-r--r-- | drivers/gpu/drm/display/drm_dp_helper.c | 42 | ||||
| -rw-r--r-- | drivers/gpu/drm/drm_edid.c | 8 | ||||
| -rw-r--r-- | include/drm/display/drm_dp_helper.h | 6 | ||||
| -rw-r--r-- | include/drm/drm_edid.h | 3 |
4 files changed, 46 insertions, 13 deletions
diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c index ea78c6c8ca7a..2d4e93683946 100644 --- a/drivers/gpu/drm/display/drm_dp_helper.c +++ b/drivers/gpu/drm/display/drm_dp_helper.c @@ -692,6 +692,34 @@ void drm_dp_dpcd_set_powered(struct drm_dp_aux *aux, bool powered) EXPORT_SYMBOL(drm_dp_dpcd_set_powered); /** + * drm_dp_dpcd_set_probe() - Set whether a probing before DPCD access is done + * @aux: DisplayPort AUX channel + * @enable: Enable the probing if required + */ +void drm_dp_dpcd_set_probe(struct drm_dp_aux *aux, bool enable) +{ + WRITE_ONCE(aux->dpcd_probe_disabled, !enable); +} +EXPORT_SYMBOL(drm_dp_dpcd_set_probe); + +static bool dpcd_access_needs_probe(struct drm_dp_aux *aux) +{ + /* + * HP ZR24w corrupts the first DPCD access after entering power save + * mode. Eg. on a read, the entire buffer will be filled with the same + * byte. Do a throw away read to avoid corrupting anything we care + * about. Afterwards things will work correctly until the monitor + * gets woken up and subsequently re-enters power save mode. + * + * The user pressing any button on the monitor is enough to wake it + * up, so there is no particularly good place to do the workaround. + * We just have to do it before any DPCD access and hope that the + * monitor doesn't power down exactly after the throw away read. + */ + return !aux->is_remote && !READ_ONCE(aux->dpcd_probe_disabled); +} + +/** * drm_dp_dpcd_read() - read a series of bytes from the DPCD * @aux: DisplayPort AUX channel (SST or MST) * @offset: address of the (first) register to read @@ -712,19 +740,7 @@ ssize_t drm_dp_dpcd_read(struct drm_dp_aux *aux, unsigned int offset, { int ret; - /* - * HP ZR24w corrupts the first DPCD access after entering power save - * mode. Eg. on a read, the entire buffer will be filled with the same - * byte. Do a throw away read to avoid corrupting anything we care - * about. Afterwards things will work correctly until the monitor - * gets woken up and subsequently re-enters power save mode. - * - * The user pressing any button on the monitor is enough to wake it - * up, so there is no particularly good place to do the workaround. - * We just have to do it before any DPCD access and hope that the - * monitor doesn't power down exactly after the throw away read. - */ - if (!aux->is_remote) { + if (dpcd_access_needs_probe(aux)) { ret = drm_dp_dpcd_probe(aux, DP_TRAINING_PATTERN_SET); if (ret < 0) return ret; diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 9cca1e6e4736..9c8822b337e2 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -248,6 +248,14 @@ static const struct edid_quirk { /* OSVR HDK and HDK2 VR Headsets */ EDID_QUIRK('S', 'V', 'R', 0x1019, BIT(EDID_QUIRK_NON_DESKTOP)), EDID_QUIRK('A', 'U', 'O', 0x1111, BIT(EDID_QUIRK_NON_DESKTOP)), + + /* + * @drm_edid_internal_quirk entries end here, following with the + * @drm_edid_quirk entries. + */ + + /* HP ZR24w DP AUX DPCD access requires probing to prevent corruption. */ + EDID_QUIRK('H', 'W', 'P', 0x2869, BIT(DRM_EDID_QUIRK_DP_DPCD_PROBE)), }; /* diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h index e4ca35143ff9..3e35a68b2b41 100644 --- a/include/drm/display/drm_dp_helper.h +++ b/include/drm/display/drm_dp_helper.h @@ -523,10 +523,16 @@ struct drm_dp_aux { * @no_zero_sized: If the hw can't use zero sized transfers (NVIDIA) */ bool no_zero_sized; + + /** + * @dpcd_probe_disabled: If probing before a DPCD access is disabled. + */ + bool dpcd_probe_disabled; }; int drm_dp_dpcd_probe(struct drm_dp_aux *aux, unsigned int offset); void drm_dp_dpcd_set_powered(struct drm_dp_aux *aux, bool powered); +void drm_dp_dpcd_set_probe(struct drm_dp_aux *aux, bool enable); ssize_t drm_dp_dpcd_read(struct drm_dp_aux *aux, unsigned int offset, void *buffer, size_t size); ssize_t drm_dp_dpcd_write(struct drm_dp_aux *aux, unsigned int offset, diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h index 77fd42608e70..3d1aecfec9b2 100644 --- a/include/drm/drm_edid.h +++ b/include/drm/drm_edid.h @@ -110,6 +110,9 @@ struct detailed_data_string { #define DRM_EDID_CVT_FLAGS_REDUCED_BLANKING (1 << 4) enum drm_edid_quirk { + /* Do a dummy read before DPCD accesses, to prevent corruption. */ + DRM_EDID_QUIRK_DP_DPCD_PROBE, + DRM_EDID_QUIRK_NUM, }; |