diff options
Diffstat (limited to 'include/drm/display')
| -rw-r--r-- | include/drm/display/drm_dp_helper.h | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h index dca40a045dd6..dc3c02225fcf 100644 --- a/include/drm/display/drm_dp_helper.h +++ b/include/drm/display/drm_dp_helper.h @@ -370,9 +370,19 @@ struct drm_dp_aux { * helpers assume this is the case. * * Also note that this callback can be called no matter the - * state @dev is in. Drivers that need that device to be powered - * to perform this operation will first need to make sure it's - * been properly enabled. + * state @dev is in and also no matter what state the panel is + * in. It's expected: + * - If the @dev providing the AUX bus is currently unpowered then + * it will power itself up for the transfer. + * - If we're on eDP (using a drm_panel) and the panel is not in a + * state where it can respond (it's not powered or it's in a + * low power state) then this function may return an error, but + * not crash. It's up to the caller of this code to make sure that + * the panel is powered on if getting an error back is not OK. If a + * drm_panel driver is initiating a DP AUX transfer it may power + * itself up however it wants. All other code should ensure that + * the pre_enable() bridge chain (which eventually calls the + * drm_panel prepare function) has powered the panel. */ ssize_t (*transfer)(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg); |