On Tue, 15 Nov 2022 at 12:27, Pin-yen Lin <treapking@xxxxxxxxxxxx> wrote:
>
> Add caching when EDID is read, and invalidate the cache until the
> bridge detects HPD low or sink count changes on HPD_IRQ.
>
> It takes 1.2s for IT6505 bridge to read a 3-block EDID, and skipping
> one EDID read would be a notable difference on user experience.
>
> Signed-off-by: Pin-yen Lin <treapking@xxxxxxxxxxxx>
>
> ---
>
> drivers/gpu/drm/bridge/ite-it6505.c | 26 ++++++++++++++++++++------
> 1 file changed, 20 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
> index 21a9b8422bda..4b818f31668f 100644
> --- a/drivers/gpu/drm/bridge/ite-it6505.c
> +++ b/drivers/gpu/drm/bridge/ite-it6505.c
> @@ -457,6 +457,8 @@ struct it6505 {
>
> /* it6505 driver hold option */
> bool enable_drv_hold;
> +
> + struct edid *cached_edid;
> };
>
> struct it6505_step_train_para {
> @@ -2244,6 +2246,13 @@ static void it6505_plugged_status_to_codec(struct it6505 *it6505)
> status == connector_status_connected);
> }
>
> +
> +static void it6505_remove_edid(struct it6505 *it6505)
> +{
> + kfree(it6505->cached_edid);
> + it6505->cached_edid = NULL;
> +}
> +
> static int it6505_process_hpd_irq(struct it6505 *it6505)
> {
> struct device *dev = &it6505->client->dev;
> @@ -2270,6 +2279,7 @@ static int it6505_process_hpd_irq(struct it6505 *it6505)
> it6505_reset_logic(it6505);
> it6505_int_mask_enable(it6505);
> it6505_init(it6505);
> + it6505_remove_edid(it6505);
> return 0;
> }
>
> @@ -2353,6 +2363,7 @@ static void it6505_irq_hpd(struct it6505 *it6505)
> it6505_video_reset(it6505);
> } else {
> memset(it6505->dpcd, 0, sizeof(it6505->dpcd));
> + it6505_remove_edid(it6505);
>
> if (it6505->hdcp_desired)
> it6505_stop_hdcp(it6505);
> @@ -3016,16 +3027,18 @@ static struct edid *it6505_bridge_get_edid(struct drm_bridge *bridge,
> {
> struct it6505 *it6505 = bridge_to_it6505(bridge);
> struct device *dev = &it6505->client->dev;
> - struct edid *edid;
>
> - edid = drm_do_get_edid(connector, it6505_get_edid_block, it6505);
> + if (!it6505->cached_edid) {
> + it6505->cached_edid = drm_do_get_edid(connector, it6505_get_edid_block,
> + it6505);
>
> - if (!edid) {
> - DRM_DEV_DEBUG_DRIVER(dev, "failed to get edid!");
> - return NULL;
> + if (!it6505->cached_edid) {
> + DRM_DEV_DEBUG_DRIVER(dev, "failed to get edid!");
> + return NULL;
> + }
> }
>
> - return edid;
> + return drm_edid_duplicate(it6505->cached_edid);
> }
>
> static const struct drm_bridge_funcs it6505_bridge_funcs = {
> @@ -3367,6 +3380,7 @@ static void it6505_i2c_remove(struct i2c_client *client)
> drm_dp_aux_unregister(&it6505->aux);
> it6505_debugfs_remove(it6505);
> it6505_poweroff(it6505);
> + it6505_remove_edid(it6505);
> }
>
> static const struct i2c_device_id it6505_id[] = {
> --
> 2.38.1.493.g58b659f92b-goog
>
Reviewed-by: Robert Foss <robert.foss@xxxxxxxxxx>
