On Thu, 2022-07-07 at 13:14 +0800, CK Hu wrote: > Hi, Bo-Chen: > > On Fri, 2022-07-01 at 14:28 +0800, Bo-Chen Chen wrote: > > From: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx> > > > > This patch adds a embedded 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 > > Jitao shi <jitao.shi@xxxxxxxxxxxx> > > > > Signed-off-by: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx> > > Signed-off-by: Guillaume Ranquet <granquet@xxxxxxxxxxxx> > > Signed-off-by: Bo-Chen Chen <rex-bc.chen@xxxxxxxxxxxx> > > --- > > [snip] > > > + > > +static ssize_t mtk_dp_hpd_sink_event(struct mtk_dp *mtk_dp) > > The caller never use the return value, so let this function to void. > > > +{ > > + ssize_t ret; > > + u8 sink_count; > > + 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); > > You read sink_count but never use it, so this read is redundant. > Remove > it. > Hello CK, this is a pre-request for the following codes, so I think we need to keep this. If we failed to read sink_count, we don't need to do the driver under this. > > + if (ret < 1) { > > + drm_err(mtk_dp->drm_dev, "Read sink count failed\n"); > > + return ret == 0 ? -EIO : 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\n"); > > + return ret; > > + } > > + > > + drm_dp_channel_eq_ok(link_status, mtk_dp- > > > train_info.lane_count); > > This function just return true or false, and you does not process the > return value, so this is redundant. Remove it. > I will handle this in next version. BRs, Bo-Chen > Regard, > CK > > > + > > + 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); > > + > > + return 0; > > +} > >