Messages in this thread | | | Subject | Re: [PATCH v10 18/21] drm/mediatek: Add mt8195 Embedded DisplayPort driver | From | CK Hu <> | Date | Tue, 7 Jun 2022 14:44:32 +0800 |
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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_train_handler(struct mtk_dp *mtk_dp) > +{ > + bool training_done = false; > + short max_retry = 50; > + int ret = 0; > + > + do { > + switch (mtk_dp->train_state) { > + case MTK_DP_TRAIN_STATE_STARTUP:
mtk_dp->train_state is initialized as MTK_DP_TRAIN_STATE_STARTUP even though HPD ISR does not exist. Does this mean HPD ISR is redundant? If HPD ISR is not redundant, create a new state MTK_DP_TRAIN_STATE_NONE for init state.
> + mtk_dp_state_handler(mtk_dp); > + mtk_dp->train_state = > MTK_DP_TRAIN_STATE_CHECKCAP; > + break; > + > + case MTK_DP_TRAIN_STATE_CHECKCAP: > + if (mtk_dp_parse_capabilities(mtk_dp)) { > + mtk_dp->train_info.check_cap_count = 0; > + mtk_dp->train_state = > MTK_DP_TRAIN_STATE_CHECKEDID; > + } else { > + mtk_dp->train_info.check_cap_count++; > + > + if (mtk_dp->train_info.check_cap_count > > > + MTK_DP_CHECK_SINK_CAP_TIMEOUT_COUNT > ) { > + mtk_dp- > >train_info.check_cap_count = 0; > + mtk_dp->train_state = > MTK_DP_TRAIN_STATE_DPIDLE; > + ret = -ETIMEDOUT; > + } > + } > + break; > + > + case MTK_DP_TRAIN_STATE_CHECKEDID: > + mtk_dp->train_state = > MTK_DP_TRAIN_STATE_TRAINING_PRE;
MTK_DP_TRAIN_STATE_CHECKEDID is a redundant state, drop it.
> + break; > + > + case MTK_DP_TRAIN_STATE_TRAINING_PRE: > + mtk_dp_state_handler(mtk_dp); > + mtk_dp->train_state = > MTK_DP_TRAIN_STATE_TRAINING; > + break; > + > + case MTK_DP_TRAIN_STATE_TRAINING: > + ret = mtk_dp_train_start(mtk_dp); > + if (ret == 0) { > + mtk_dp_video_mute(mtk_dp, true); > + mtk_dp->train_state = > MTK_DP_TRAIN_STATE_NORMAL; > + mtk_dp_fec_enable(mtk_dp, mtk_dp- > >has_fec); > + } else if (ret != -EAGAIN) { > + mtk_dp->train_state = > MTK_DP_TRAIN_STATE_DPIDLE; > + } > + break; > + case MTK_DP_TRAIN_STATE_NORMAL: > + mtk_dp_state_handler(mtk_dp); > + training_done = true; > + break; > + case MTK_DP_TRAIN_STATE_DPIDLE:
When would this case happen?
Regards, CK
> + break; > + default: > + break; > + } > + > + if (ret) { > + if (ret == -EAGAIN) > + continue; > + /* > + * If we get any other error number, it doesn't > + * make any sense to keep iterating. > + */ > + break; > + } > + } while (!training_done || --max_retry); > + > + return ret; > +}
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