Hi, Rex:
On Wed, 2022-06-08 at 18:26 +0800, Rex-BC Chen wrote:
On Tue, 2022-06-07 at 15:47 +0800, CK Hu wrote:
Hi, Rex:
On Mon, 2022-05-23 at 12:47 +0200, Guillaume Ranquet wrote:
From: Markus Schneider-Pargmann msp@baylibre.com
This patch adds a DisplayPort driver for the Mediatek mt8195 SoC.
It supports the mt8195, the embedded DisplayPort units. It offers DisplayPort 1.4 with up to 4 lanes.
The driver creates a child device for the phy. The child device will never exist without the parent being active. As they are sharing a register range, the parent passes a regmap pointer to the child so that both can work with the same register range. The phy driver sets device data that is read by the parent to get the phy device that can be used to control the phy properties.
This driver is based on an initial version by Jason-JH.Lin jason-jh.lin@mediatek.com.
Signed-off-by: Markus Schneider-Pargmann msp@baylibre.com Signed-off-by: Guillaume Ranquet granquet@baylibre.com
[snip]
+static int mtk_dp_hpd_sink_event(struct mtk_dp *mtk_dp) +{
- ssize_t ret;
- u8 sink_count;
- bool locked;
- u8 link_status[DP_LINK_STATUS_SIZE] = {};
- u32 sink_count_reg = DP_SINK_COUNT_ESI;
- u32 link_status_reg = DP_LANE0_1_STATUS;
- ret = drm_dp_dpcd_readb(&mtk_dp->aux, sink_count_reg,
&sink_count);
- if (ret < 0) {
drm_err(mtk_dp->drm_dev, "Read sink count failed:%ld\n", ret);
return ret;- }
- ret = drm_dp_dpcd_read(&mtk_dp->aux, link_status_reg,
link_status,
sizeof(link_status));- if (!ret) {
drm_err(mtk_dp->drm_dev, "Read link status failed:%ld\n",
ret);return ret;- }
- locked = drm_dp_channel_eq_ok(link_status,
mtk_dp->train_info.lane_count);- if (!locked && mtk_dp->train_state >
MTK_DP_TRAIN_STATE_TRAINING_PRE)
Before enter this function, mtk_dp->train_state is set to MTK_DP_TRAIN_STATE_STARTUP, so this never happen, drop this.
The interrupt from sink device could come any time. Why it's impossible?
I still ask this question: "For eDP, when does disconnect happened?" If it indeed happen, I still do not like to change state here. When disconnect, the training flow would result in fail finally and need not to change state here, but the training flow would block for a while when disconnect. You could add some check point to check train_info-
cable_plugged_in to quickly break out the training flow.
Regards, CK
mtk_dp->train_state = MTK_DP_TRAIN_STATE_TRAINING_PRE;- if (link_status[1] & DP_REMOTE_CONTROL_COMMAND_PENDING)
drm_dp_dpcd_writeb(&mtk_dp->aux,DP_DEVICE_SERVICE_IRQ_VECTOR,
DP_REMOTE_CONTROL_COMMAND_PENDING);- if (DP_GET_SINK_COUNT(sink_count) &&
(link_status[2] & DP_DOWNSTREAM_PORT_STATUS_CHANGED)) {mtk_dp->train_info.check_cap_count = 0;mtk_dp->train_state = MTK_DP_TRAIN_STATE_CHECKEDID;Why change state from MTK_DP_TRAIN_STATE_STARTUP to MTK_DP_TRAIN_STATE_CHECKEDID? In mtk_dp_train_handler(), mtk_dp_parse_capabilities() is true then change to MTK_DP_TRAIN_STATE_CHECKEDID. Give a reason why these two are different.
Regards, CK
I will drop this and drop state of MTK_DP_TRAIN_STATE_CHECKEDID. MTK_DP_TRAIN_STATE_CHECKEDID is only used for audio. We can check enable status in another place.
BRs, Bo-Chen
msleep(20);- }
- return 0;
+}