6.6-stable review patch. If anyone has any objections, please let me know.
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From: Douglas Anderson dianders@chromium.org
[ Upstream commit 024b32db43a359e0ded3fcc6cd86247cbbed4224 ]
Unlike what is claimed in commit f5aa7d46b0ee ("drm/bridge: parade-ps8640: Provide wait_hpd_asserted() in struct drm_dp_aux"), if someone manually tries to do an AUX transfer (like via `i2cdump ${bus} 0x50 i`) while the panel is off we don't just get a simple transfer error. Instead, the whole ps8640 gets thrown for a loop and goes into a bad state.
Let's put the function to wait for the HPD (and the magical 50 ms after first reset) back in when we're doing an AUX transfer. This shouldn't actually make things much slower (assuming the panel is on) because we should immediately poll and see the HPD high. Mostly this is just an extra i2c transfer to the bridge.
Fixes: f5aa7d46b0ee ("drm/bridge: parade-ps8640: Provide wait_hpd_asserted() in struct drm_dp_aux") Tested-by: Pin-yen Lin treapking@chromium.org Reviewed-by: Pin-yen Lin treapking@chromium.org Signed-off-by: Douglas Anderson dianders@chromium.org Link: https://patchwork.freedesktop.org/patch/msgid/20231221135548.1.I10f326a9305d... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/bridge/parade-ps8640.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c index 541e4f5afc4c..fb5e9ae9ad81 100644 --- a/drivers/gpu/drm/bridge/parade-ps8640.c +++ b/drivers/gpu/drm/bridge/parade-ps8640.c @@ -346,6 +346,11 @@ static ssize_t ps8640_aux_transfer(struct drm_dp_aux *aux, int ret;
pm_runtime_get_sync(dev); + ret = _ps8640_wait_hpd_asserted(ps_bridge, 200 * 1000); + if (ret) { + pm_runtime_put_sync_suspend(dev); + return ret; + } ret = ps8640_aux_transfer_msg(aux, msg); pm_runtime_mark_last_busy(dev); pm_runtime_put_autosuspend(dev);