drm: Mention the power state requirement on side-channel operations
authorMaxime Ripard <maxime@cerno.tech>
Wed, 16 Jun 2021 14:15:29 +0000 (16:15 +0200)
committerMaxime Ripard <maxime@cerno.tech>
Wed, 23 Jun 2021 12:32:27 +0000 (14:32 +0200)
commitbacbab58f09dcf7c9a52b9f11388b3e25b9daa5f
tree6358fbcfee0ccb6f03f078ec984967025f3cf0e8
parentc48935ab6b1280a80b38405369e88470f49809f4
drm: Mention the power state requirement on side-channel operations

The drm_connector detect, drm_dp_aux transfer and mipi_dsi_host
operations typically require to access their underlying device to
perform what is expected of them.

However, there's no guarantee on the fact that the device has been
enabled through atomic_enable or similar that will usually power the
device. The access to an unpowered device is then an undefined behaviour
ranging from the access being ignored to a hard CPU hang.

Let's document that expectation to avoid as much as possible those
consequences.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210616141529.630719-3-maxime@cerno.tech
include/drm/drm_connector.h
include/drm/drm_dp_helper.h
include/drm/drm_mipi_dsi.h