Hi Jayesh, Thank you for the patch.
On Wed, Apr 05, 2023 at 07:54:40PM +0530, Jayesh Choudhary wrote: > From: Rahul T R <[email protected]> > > In J721S2 EVMs DP0 hpd is not connected to correct > hpd pin on SOC, to handle such cases, Add support for > "no-hpd" property in the device tree node to disable > hpd s/hpd/hpd./ You can also reflow the commit message to 72 columns. > Also change the log level for dpcd read failuers to > debug, since framework retries 32 times for each read s/read/read./ Doesn't this apply to writes as well ? > Signed-off-by: Rahul T R <[email protected]> > Signed-off-by: Jayesh Choudhary <[email protected]> > --- > .../drm/bridge/cadence/cdns-mhdp8546-core.c | 37 ++++++++++++++++--- > .../drm/bridge/cadence/cdns-mhdp8546-core.h | 1 + > 2 files changed, 33 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > index f6822dfa3805..e177794b069d 100644 > --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > @@ -54,6 +54,8 @@ > #include "cdns-mhdp8546-hdcp.h" > #include "cdns-mhdp8546-j721e.h" > > +static int cdns_mhdp_update_link_status(struct cdns_mhdp_device *mhdp); > + > static int cdns_mhdp_mailbox_read(struct cdns_mhdp_device *mhdp) > { > int ret, empty; > @@ -749,7 +751,7 @@ static int cdns_mhdp_fw_activate(const struct firmware > *fw, > * MHDP_HW_STOPPED happens only due to driver removal when > * bridge should already be detached. > */ > - if (mhdp->bridge_attached) > + if (mhdp->bridge_attached && !mhdp->no_hpd) > writel(~(u32)CDNS_APB_INT_MASK_SW_EVENT_INT, > mhdp->regs + CDNS_APB_INT_MASK); > > @@ -845,7 +847,7 @@ static ssize_t cdns_mhdp_transfer(struct drm_dp_aux *aux, > ret = cdns_mhdp_dpcd_read(mhdp, msg->address, > msg->buffer, msg->size); > if (ret) { > - dev_err(mhdp->dev, > + dev_dbg(mhdp->dev, > "Failed to read DPCD addr %u\n", > msg->address); > > @@ -1738,6 +1740,19 @@ static int cdns_mhdp_attach(struct drm_bridge *bridge, > > spin_unlock(&mhdp->start_lock); > > + if (mhdp->no_hpd) { > + ret = wait_event_timeout(mhdp->fw_load_wq, > + mhdp->hw_state == MHDP_HW_READY, > + msecs_to_jiffies(100)); > + if (ret == 0) { > + dev_err(mhdp->dev, "%s: Timeout waiting for fw > loading\n", > + __func__); > + return -ETIMEDOUT; > + } > + > + cdns_mhdp_update_link_status(mhdp); > + return 0; > + } Missing blank line. It's not clear to me while you need to wait for the state to change to MHDP_HW_READY in the no_hpd case. This should be explained in the commit message. > /* Enable SW event interrupts */ > if (hw_ready) > writel(~(u32)CDNS_APB_INT_MASK_SW_EVENT_INT, > @@ -2256,7 +2271,16 @@ static int cdns_mhdp_update_link_status(struct > cdns_mhdp_device *mhdp) > > mutex_lock(&mhdp->link_mutex); > > - mhdp->plugged = cdns_mhdp_detect_hpd(mhdp, &hpd_pulse); > + if (mhdp->no_hpd) { > + ret = drm_dp_dpcd_read_link_status(&mhdp->aux, status); > + hpd_pulse = false; > + if (ret < 0) > + mhdp->plugged = false; > + else > + mhdp->plugged = true; I think there's an issue with how the driver uses mhdp->plugged. In the no_hpd case, you try to detect if a display is connected by reading the link status at attach time, and then never update mhdp->plugged. This means that if no display is connected at that point, functions like cdns_mhdp_get_edid() will always fail, even if a display gets plugged later. As the goal of this series is (as far as I understand) support systems where the HPD signal could be connected to a SoC GPIO instead of the bridge, I don't think this is good enough. > + } else { > + mhdp->plugged = cdns_mhdp_detect_hpd(mhdp, &hpd_pulse); > + } > > if (!mhdp->plugged) { > cdns_mhdp_link_down(mhdp); > @@ -2451,6 +2475,8 @@ static int cdns_mhdp_probe(struct platform_device *pdev) > mhdp->aux.dev = dev; > mhdp->aux.transfer = cdns_mhdp_transfer; > > + mhdp->no_hpd = of_property_read_bool(dev->of_node, "cdns,no-hpd"); > + > mhdp->regs = devm_platform_ioremap_resource(pdev, 0); > if (IS_ERR(mhdp->regs)) { > dev_err(dev, "Failed to get memory resource\n"); > @@ -2526,8 +2552,9 @@ static int cdns_mhdp_probe(struct platform_device *pdev) > > mhdp->bridge.of_node = pdev->dev.of_node; > mhdp->bridge.funcs = &cdns_mhdp_bridge_funcs; > - mhdp->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID | > - DRM_BRIDGE_OP_HPD; > + mhdp->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID; > + if (!mhdp->no_hpd) > + mhdp->bridge.ops |= DRM_BRIDGE_OP_HPD; > mhdp->bridge.type = DRM_MODE_CONNECTOR_DisplayPort; > if (mhdp->info) > mhdp->bridge.timings = mhdp->info->timings; > diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h > b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h > index bedddd510d17..6786ccb51387 100644 > --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h > +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h > @@ -388,6 +388,7 @@ struct cdns_mhdp_device { > > bool link_up; > bool plugged; > + bool no_hpd; > > /* > * "start_lock" protects the access to bridge_attached and -- Regards, Laurent Pinchart
