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drm/bridge: parade-ps8640: Wait for HPD when doing an AUX transfer

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[ Upstream commit 024b32db43a359e0ded3fcc6cd86247cbbed4224 ]

Unlike what is claimed in commit f5aa7d46b0 ("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: f5aa7d46b0 ("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.I10f326a9305d57ad32cee7f8d9c60518c8be20fb@changeid
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Douglas Anderson 2023-12-21 13:55:48 -08:00 committed by Greg Kroah-Hartman
parent f9a4c401bf
commit 6b7fb2903a
1 changed files with 5 additions and 0 deletions
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5
drivers/gpu/drm/bridge/parade-ps8640.c
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@ -354,6 +354,11 @@ 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);