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SubjectRe: [PATCH] drm/bridge: it6505: Send DPCD SET_POWER to downstream
On Mon, 25 Apr 2022 at 15:44, Pin-Yen Lin <treapking@chromium.org> wrote:
>
> Send DPCD SET_POWER command to downstream in .atomic_disable to make the
> downstream monitor enter the power down mode, so the device suspend won't
> be affected.
>
> Fixes: b5c84a9edcd418 ("drm/bridge: add it6505 driver")
> Signed-off-by: Pin-Yen Lin <treapking@chromium.org>
> ---
>
> drivers/gpu/drm/bridge/ite-it6505.c | 29 ++++++++++++++++++-----------
> 1 file changed, 18 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
> index 8fed30df08b0..4b673c4792d7 100644
> --- a/drivers/gpu/drm/bridge/ite-it6505.c
> +++ b/drivers/gpu/drm/bridge/ite-it6505.c
> @@ -737,8 +737,9 @@ static int it6505_drm_dp_link_probe(struct drm_dp_aux *aux,
> return 0;
> }
>
> -static int it6505_drm_dp_link_power_up(struct drm_dp_aux *aux,
> - struct it6505_drm_dp_link *link)
> +static int it6505_drm_dp_link_set_power(struct drm_dp_aux *aux,
> + struct it6505_drm_dp_link *link,
> + u8 mode)
> {
> u8 value;
> int err;
> @@ -752,18 +753,20 @@ static int it6505_drm_dp_link_power_up(struct drm_dp_aux *aux,
> return err;
>
> value &= ~DP_SET_POWER_MASK;
> - value |= DP_SET_POWER_D0;
> + value |= mode;
>
> err = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value);
> if (err < 0)
> return err;
>
> - /*
> - * According to the DP 1.1 specification, a "Sink Device must exit the
> - * power saving state within 1 ms" (Section 2.5.3.1, Table 5-52, "Sink
> - * Control Field" (register 0x600).
> - */
> - usleep_range(1000, 2000);
> + if (mode == DP_SET_POWER_D0) {
> + /*
> + * According to the DP 1.1 specification, a "Sink Device must
> + * exit the power saving state within 1 ms" (Section 2.5.3.1,
> + * Table 5-52, "Sink Control Field" (register 0x600).
> + */
> + usleep_range(1000, 2000);
> + }
>
> return 0;
> }
> @@ -2624,7 +2627,8 @@ static enum drm_connector_status it6505_detect(struct it6505 *it6505)
> if (it6505_get_sink_hpd_status(it6505)) {
> it6505_aux_on(it6505);
> it6505_drm_dp_link_probe(&it6505->aux, &it6505->link);
> - it6505_drm_dp_link_power_up(&it6505->aux, &it6505->link);
> + it6505_drm_dp_link_set_power(&it6505->aux, &it6505->link,
> + DP_SET_POWER_D0);
> it6505->auto_train_retry = AUTO_TRAIN_RETRY;
>
> if (it6505->dpcd[0] == 0) {
> @@ -2960,8 +2964,11 @@ static void it6505_bridge_atomic_disable(struct drm_bridge *bridge,
>
> DRM_DEV_DEBUG_DRIVER(dev, "start");
>
> - if (it6505->powered)
> + if (it6505->powered) {
> it6505_video_disable(it6505);
> + it6505_drm_dp_link_set_power(&it6505->aux, &it6505->link,
> + DP_SET_POWER_D3);
> + }
> }
>
> static enum drm_connector_status
> --
> 2.36.0.rc2.479.g8af0fa9b8e-goog
>

Reviewed-by: Robert Foss <robert.foss@linaro.org>

Applied to drm-misc-next.

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