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Commit 3623f833 authored by Brian Norris's avatar Brian Norris Committed by Greg Kroah-Hartman
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drm/bridge: analogix_dp: Grab runtime PM reference for DP-AUX 



commit 8fb6c44fe8468f92ac7b8bbfcca4404a4e88645f upstream.

If the display is not enable()d, then we aren't holding a runtime PM
reference here. Thus, it's easy to accidentally cause a hang, if user
space is poking around at /dev/drm_dp_aux0 at the "wrong" time.

Let's get a runtime PM reference, and check that we "see" the panel.
Don't force any panel power-up, etc., because that can be intrusive, and
that's not what other drivers do (see
drivers/gpu/drm/bridge/ti-sn65dsi86.c and
drivers/gpu/drm/bridge/parade-ps8640.c.)

Fixes: 0d97ad03 ("drm/bridge: analogix_dp: Remove duplicated code")
Cc: <stable@vger.kernel.org>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: default avatarBrian Norris <briannorris@chromium.org>
Reviewed-by: default avatarDouglas Anderson <dianders@chromium.org>
Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220301181107.v4.1.I773a08785666ebb236917b0c8e6c05e3de471e75@changeid


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8fa6eb03

drivers/gpu/drm/bridge/analogix/analogix_dp_core.c

+12 −1
Original line number Diff line number Diff line
@@ -1630,8 +1630,19 @@ static ssize_t analogix_dpaux_transfer(struct drm_dp_aux *aux, 
				       struct drm_dp_aux_msg *msg)

{

	struct analogix_dp_device *dp = to_dp(aux);

	int ret;



	pm_runtime_get_sync(dp->dev);



	return analogix_dp_transfer(dp, msg);

	ret = analogix_dp_detect_hpd(dp);

	if (ret)

		goto out;



	ret = analogix_dp_transfer(dp, msg);

out:

	pm_runtime_put(dp->dev);



	return ret;

}



struct analogix_dp_device *