| From 8fb6c44fe8468f92ac7b8bbfcca4404a4e88645f Mon Sep 17 00:00:00 2001 |
| From: Brian Norris <briannorris@chromium.org> |
| Date: Tue, 1 Mar 2022 18:11:38 -0800 |
| Subject: drm/bridge: analogix_dp: Grab runtime PM reference for DP-AUX |
| |
| From: Brian Norris <briannorris@chromium.org> |
| |
| 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: 0d97ad03f422 ("drm/bridge: analogix_dp: Remove duplicated code") |
| Cc: <stable@vger.kernel.org> |
| Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com> |
| Signed-off-by: Brian Norris <briannorris@chromium.org> |
| Reviewed-by: Douglas Anderson <dianders@chromium.org> |
| Signed-off-by: Douglas Anderson <dianders@chromium.org> |
| Link: https://patchwork.freedesktop.org/patch/msgid/20220301181107.v4.1.I773a08785666ebb236917b0c8e6c05e3de471e75@changeid |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 13 ++++++++++++- |
| 1 file changed, 12 insertions(+), 1 deletion(-) |
| |
| --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c |
| +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c |
| @@ -1275,8 +1275,19 @@ static ssize_t analogix_dpaux_transfer(s |
| struct drm_dp_aux_msg *msg) |
| { |
| struct analogix_dp_device *dp = to_dp(aux); |
| + int ret; |
| |
| - return analogix_dp_transfer(dp, msg); |
| + pm_runtime_get_sync(dp->dev); |
| + |
| + ret = analogix_dp_detect_hpd(dp); |
| + if (ret) |
| + goto out; |
| + |
| + ret = analogix_dp_transfer(dp, msg); |
| +out: |
| + pm_runtime_put(dp->dev); |
| + |
| + return ret; |
| } |
| |
| int analogix_dp_bind(struct device *dev, struct drm_device *drm_dev, |