The source device should ensure the sink is ready before proceeding to
read the sink capability or performing any aux transactions. The sink
will indicate its readiness by asserting the HPD line. The controller
driver needs to wait for the hpd line to be asserted by the sink before
performing any aux transactions.
The eDP sink is assumed to be always connected. It needs power from the
source and its HPD line will be asserted only after the panel is powered
on. The panel power will be enabled from the panel-edp driver and only
after that, the hpd line will be asserted.
Whereas for DP, the sink can be hotplugged and unplugged anytime. The hpd
line gets asserted to indicate the sink is connected and ready. Hence
there is no need to wait for the hpd line to be asserted for a DP sink.
Signed-off-by: Sankeerth Billakanti <[email protected]>
---
Changes in v6:
- Wait for hpd high only for eDP
- Split into smaller patches
drivers/gpu/drm/msm/dp/dp_aux.c | 13 ++++++++++++-
drivers/gpu/drm/msm/dp/dp_aux.h | 3 ++-
drivers/gpu/drm/msm/dp/dp_catalog.c | 13 +++++++++++++
drivers/gpu/drm/msm/dp/dp_catalog.h | 1 +
drivers/gpu/drm/msm/dp/dp_display.c | 3 ++-
5 files changed, 30 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
index 6d36f63..a217c80 100644
--- a/drivers/gpu/drm/msm/dp/dp_aux.c
+++ b/drivers/gpu/drm/msm/dp/dp_aux.c
@@ -36,6 +36,7 @@ struct dp_aux_private {
bool initted;
u32 offset;
u32 segment;
+ bool is_edp;
struct drm_dp_aux dp_aux;
};
@@ -337,6 +338,14 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
goto exit;
}
+ if (aux->is_edp) {
+ ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog);
+ if (ret) {
+ DRM_DEBUG_DP("Panel not ready for aux transactions\n");
+ goto exit;
+ }
+ }
+
dp_aux_update_offset_and_segment(aux, msg);
dp_aux_transfer_helper(aux, msg, true);
@@ -491,7 +500,8 @@ void dp_aux_unregister(struct drm_dp_aux *dp_aux)
drm_dp_aux_unregister(dp_aux);
}
-struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog)
+struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
+ bool is_edp)
{
struct dp_aux_private *aux;
@@ -506,6 +516,7 @@ struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog)
init_completion(&aux->comp);
aux->cmd_busy = false;
+ aux->is_edp = is_edp;
mutex_init(&aux->mutex);
aux->dev = dev;
diff --git a/drivers/gpu/drm/msm/dp/dp_aux.h b/drivers/gpu/drm/msm/dp/dp_aux.h
index 82afc8d..c99aeec 100644
--- a/drivers/gpu/drm/msm/dp/dp_aux.h
+++ b/drivers/gpu/drm/msm/dp/dp_aux.h
@@ -16,7 +16,8 @@ void dp_aux_init(struct drm_dp_aux *dp_aux);
void dp_aux_deinit(struct drm_dp_aux *dp_aux);
void dp_aux_reconfig(struct drm_dp_aux *dp_aux);
-struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog);
+struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
+ bool is_edp);
void dp_aux_put(struct drm_dp_aux *aux);
#endif /*__DP_AUX_H_*/
diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c b/drivers/gpu/drm/msm/dp/dp_catalog.c
index fac815f..b6add4e 100644
--- a/drivers/gpu/drm/msm/dp/dp_catalog.c
+++ b/drivers/gpu/drm/msm/dp/dp_catalog.c
@@ -242,6 +242,19 @@ void dp_catalog_aux_update_cfg(struct dp_catalog *dp_catalog)
phy_calibrate(phy);
}
+int dp_catalog_aux_wait_for_hpd_connect_state(struct dp_catalog *dp_catalog)
+{
+ u32 state;
+ struct dp_catalog_private *catalog = container_of(dp_catalog,
+ struct dp_catalog_private, dp_catalog);
+
+ /* poll for hpd connected status every 2ms and timeout after 500ms */
+ return readl_poll_timeout(catalog->io->dp_controller.aux.base +
+ REG_DP_DP_HPD_INT_STATUS,
+ state, state & DP_DP_HPD_STATE_STATUS_CONNECTED,
+ 2000, 500000);
+}
+
static void dump_regs(void __iomem *base, int len)
{
int i;
diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.h b/drivers/gpu/drm/msm/dp/dp_catalog.h
index 7dea101..45140a3 100644
--- a/drivers/gpu/drm/msm/dp/dp_catalog.h
+++ b/drivers/gpu/drm/msm/dp/dp_catalog.h
@@ -84,6 +84,7 @@ int dp_catalog_aux_clear_hw_interrupts(struct dp_catalog *dp_catalog);
void dp_catalog_aux_reset(struct dp_catalog *dp_catalog);
void dp_catalog_aux_enable(struct dp_catalog *dp_catalog, bool enable);
void dp_catalog_aux_update_cfg(struct dp_catalog *dp_catalog);
+int dp_catalog_aux_wait_for_hpd_connect_state(struct dp_catalog *dp_catalog);
u32 dp_catalog_aux_get_irq(struct dp_catalog *dp_catalog);
/* DP Controller APIs */
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index e082d02..274bbcf 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -755,6 +755,7 @@ static void dp_display_deinit_sub_modules(struct dp_display_private *dp)
static int dp_init_sub_modules(struct dp_display_private *dp)
{
int rc = 0;
+ bool is_edp = (dp->dp_display.connector_type == DRM_MODE_CONNECTOR_eDP);
struct device *dev = &dp->pdev->dev;
struct dp_usbpd_cb *cb = &dp->usbpd_cb;
struct dp_panel_in panel_in = {
@@ -798,7 +799,7 @@ static int dp_init_sub_modules(struct dp_display_private *dp)
goto error;
}
- dp->aux = dp_aux_get(dev, dp->catalog);
+ dp->aux = dp_aux_get(dev, dp->catalog, is_edp);
if (IS_ERR(dp->aux)) {
rc = PTR_ERR(dp->aux);
DRM_ERROR("failed to initialize aux, rc = %d\n", rc);
--
2.7.4
Hi,
On Wed, Mar 30, 2022 at 9:03 AM Sankeerth Billakanti
<[email protected]> wrote:
>
> The source device should ensure the sink is ready before proceeding to
> read the sink capability or performing any aux transactions. The sink
s/performing/perform
> will indicate its readiness by asserting the HPD line. The controller
> driver needs to wait for the hpd line to be asserted by the sink before
> performing any aux transactions.
>
> The eDP sink is assumed to be always connected. It needs power from the
> source and its HPD line will be asserted only after the panel is powered
> on. The panel power will be enabled from the panel-edp driver and only
> after that, the hpd line will be asserted.
>
> Whereas for DP, the sink can be hotplugged and unplugged anytime. The hpd
> line gets asserted to indicate the sink is connected and ready. Hence
> there is no need to wait for the hpd line to be asserted for a DP sink.
>
> Signed-off-by: Sankeerth Billakanti <[email protected]>
> ---
>
> Changes in v6:
> - Wait for hpd high only for eDP
> - Split into smaller patches
>
> drivers/gpu/drm/msm/dp/dp_aux.c | 13 ++++++++++++-
> drivers/gpu/drm/msm/dp/dp_aux.h | 3 ++-
> drivers/gpu/drm/msm/dp/dp_catalog.c | 13 +++++++++++++
> drivers/gpu/drm/msm/dp/dp_catalog.h | 1 +
> drivers/gpu/drm/msm/dp/dp_display.c | 3 ++-
> 5 files changed, 30 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
> index 6d36f63..a217c80 100644
> --- a/drivers/gpu/drm/msm/dp/dp_aux.c
> +++ b/drivers/gpu/drm/msm/dp/dp_aux.c
> @@ -36,6 +36,7 @@ struct dp_aux_private {
> bool initted;
> u32 offset;
> u32 segment;
> + bool is_edp;
>
> struct drm_dp_aux dp_aux;
> };
> @@ -337,6 +338,14 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
> goto exit;
> }
>
> + if (aux->is_edp) {
Adding a comment about _why_ you're doing this just for eDP would
probably be a good idea. Like maybe:
/*
* For eDP it's important to give a reasonably long wait here for HPD
* to be asserted. This is because the panel driver may have _just_
* turned on the panel and then tried to do an AUX transfer. The panel
* driver has no way of knowing when the panel is ready, so it's up
* to us to wait. For DP we never get into this situation so let's
* avoid ever doing the extra long wait for DP.
*/
> @@ -491,7 +500,8 @@ void dp_aux_unregister(struct drm_dp_aux *dp_aux)
> drm_dp_aux_unregister(dp_aux);
> }
>
> -struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog)
> +struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
> + bool is_edp)
nit: I think your indentation of the 2nd line isn't quite right.
> diff --git a/drivers/gpu/drm/msm/dp/dp_aux.h b/drivers/gpu/drm/msm/dp/dp_aux.h
> index 82afc8d..c99aeec 100644
> --- a/drivers/gpu/drm/msm/dp/dp_aux.h
> +++ b/drivers/gpu/drm/msm/dp/dp_aux.h
> @@ -16,7 +16,8 @@ void dp_aux_init(struct drm_dp_aux *dp_aux);
> void dp_aux_deinit(struct drm_dp_aux *dp_aux);
> void dp_aux_reconfig(struct drm_dp_aux *dp_aux);
>
> -struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog);
> +struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
> + bool is_edp);
nit: I think your indentation of the 2nd line isn't quite right.
Things are pretty much nits, so FWIW:
Reviewed-by: Douglas Anderson <[email protected]>
Hi Doug,
> On Wed, Mar 30, 2022 at 9:03 AM Sankeerth Billakanti
> <[email protected]> wrote:
> >
> > The source device should ensure the sink is ready before proceeding to
> > read the sink capability or performing any aux transactions. The sink
>
> s/performing/perform
>
> > will indicate its readiness by asserting the HPD line. The controller
> > driver needs to wait for the hpd line to be asserted by the sink
> > before performing any aux transactions.
> >
> > The eDP sink is assumed to be always connected. It needs power from
> > the source and its HPD line will be asserted only after the panel is
> > powered on. The panel power will be enabled from the panel-edp driver
> > and only after that, the hpd line will be asserted.
> >
> > Whereas for DP, the sink can be hotplugged and unplugged anytime. The
> > hpd line gets asserted to indicate the sink is connected and ready.
> > Hence there is no need to wait for the hpd line to be asserted for a DP sink.
> >
> > Signed-off-by: Sankeerth Billakanti <[email protected]>
> > ---
> >
> > Changes in v6:
> > - Wait for hpd high only for eDP
> > - Split into smaller patches
> >
> > drivers/gpu/drm/msm/dp/dp_aux.c | 13 ++++++++++++-
> > drivers/gpu/drm/msm/dp/dp_aux.h | 3 ++-
> > drivers/gpu/drm/msm/dp/dp_catalog.c | 13 +++++++++++++
> > drivers/gpu/drm/msm/dp/dp_catalog.h | 1 +
> > drivers/gpu/drm/msm/dp/dp_display.c | 3 ++-
> > 5 files changed, 30 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c
> > b/drivers/gpu/drm/msm/dp/dp_aux.c index 6d36f63..a217c80 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_aux.c
> > +++ b/drivers/gpu/drm/msm/dp/dp_aux.c
> > @@ -36,6 +36,7 @@ struct dp_aux_private {
> > bool initted;
> > u32 offset;
> > u32 segment;
> > + bool is_edp;
> >
> > struct drm_dp_aux dp_aux;
> > };
> > @@ -337,6 +338,14 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux
> *dp_aux,
> > goto exit;
> > }
> >
> > + if (aux->is_edp) {
>
> Adding a comment about _why_ you're doing this just for eDP would
> probably be a good idea. Like maybe:
>
> /*
> * For eDP it's important to give a reasonably long wait here for HPD
> * to be asserted. This is because the panel driver may have _just_
> * turned on the panel and then tried to do an AUX transfer. The panel
> * driver has no way of knowing when the panel is ready, so it's up
> * to us to wait. For DP we never get into this situation so let's
> * avoid ever doing the extra long wait for DP.
> */
>
>
Okay. Will add it
> > @@ -491,7 +500,8 @@ void dp_aux_unregister(struct drm_dp_aux
> *dp_aux)
> > drm_dp_aux_unregister(dp_aux); }
> >
> > -struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog
> > *catalog)
> > +struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog
> *catalog,
> > + bool is_edp)
>
> nit: I think your indentation of the 2nd line isn't quite right.
>
>
I moved bool is_edp into the next line. In vim , it was sowing fine. I'll check
> > diff --git a/drivers/gpu/drm/msm/dp/dp_aux.h
> > b/drivers/gpu/drm/msm/dp/dp_aux.h index 82afc8d..c99aeec 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_aux.h
> > +++ b/drivers/gpu/drm/msm/dp/dp_aux.h
> > @@ -16,7 +16,8 @@ void dp_aux_init(struct drm_dp_aux *dp_aux); void
> > dp_aux_deinit(struct drm_dp_aux *dp_aux); void dp_aux_reconfig(struct
> > drm_dp_aux *dp_aux);
> >
> > -struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog
> > *catalog);
> > +struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog
> *catalog,
> > + bool is_edp);
>
> nit: I think your indentation of the 2nd line isn't quite right.
>
I'll check
>
> Things are pretty much nits, so FWIW:
>
> Reviewed-by: Douglas Anderson <[email protected]>
Thank you,
Sankeerth