diff mbox series

[01/14] drm/i915/tc: Abort DP AUX transfer on a disconnected TC port

Message ID 20230316131724.359612-2-imre.deak@intel.com (mailing list archive)
State New, archived
Headers show
Series drm/i915/tc: Fix a few TypeC / MST issues | expand

Commit Message

Imre Deak March 16, 2023, 1:17 p.m. UTC
On TC ports the 4ms AUX timeout combined with the 5 * 32 retry
attempts during DPCD accesses adds a 640ms delay to each access if the
sink is disconnected. This in turn slows down a modeset during which the
sink is disconnected (for instance a disabling modeset).

Prevent the above delay by aborting AUX transfers on a TC port with a
disconnected sink.

The DP 1.4a link CTS (4.2.1.5 Source Device Inactive HPD / Inactive AUX
Test") also requires not to initiate AUX transfers on disconnected DP
ports in general, however this patch doesn't change the behavior on
non-TC ports, leaving that for a follow-up.

Reported-and-tested-by: Chris Chiu <chris.chiu@canonical.com>
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8279
Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp_aux.c | 15 +++++++++++++--
 drivers/gpu/drm/i915/display/intel_tc.c     | 15 +++++++++++----
 drivers/gpu/drm/i915/display/intel_tc.h     |  1 +
 3 files changed, 25 insertions(+), 6 deletions(-)

Comments

Kahola, Mika March 21, 2023, 11:09 a.m. UTC | #1
> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of Imre
> Deak
> Sent: Thursday, March 16, 2023 3:17 PM
> To: intel-gfx@lists.freedesktop.org
> Cc: Chris Chiu <chris.chiu@canonical.com>
> Subject: [Intel-gfx] [PATCH 01/14] drm/i915/tc: Abort DP AUX transfer on a
> disconnected TC port
> 
> On TC ports the 4ms AUX timeout combined with the 5 * 32 retry attempts
> during DPCD accesses adds a 640ms delay to each access if the sink is
> disconnected. This in turn slows down a modeset during which the sink is
> disconnected (for instance a disabling modeset).
> 
> Prevent the above delay by aborting AUX transfers on a TC port with a
> disconnected sink.
> 
> The DP 1.4a link CTS (4.2.1.5 Source Device Inactive HPD / Inactive AUX
> Test") also requires not to initiate AUX transfers on disconnected DP ports in
> general, however this patch doesn't change the behavior on non-TC ports,
> leaving that for a follow-up.
> 
> Reported-and-tested-by: Chris Chiu <chris.chiu@canonical.com>
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8279
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp_aux.c | 15 +++++++++++++--
>  drivers/gpu/drm/i915/display/intel_tc.c     | 15 +++++++++++----
>  drivers/gpu/drm/i915/display/intel_tc.h     |  1 +
>  3 files changed, 25 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c
> b/drivers/gpu/drm/i915/display/intel_dp_aux.c
> index 96967e21c94c2..eb07dc5d87099 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c
> @@ -205,8 +205,19 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp,
>  	for (i = 0; i < ARRAY_SIZE(ch_data); i++)
>  		ch_data[i] = intel_dp->aux_ch_data_reg(intel_dp, i);
> 
> -	if (is_tc_port)
> +	if (is_tc_port) {
>  		intel_tc_port_lock(dig_port);
> +		/*
> +		 * Abort transfers on a disconnected port as required by
> +		 * DP 1.4a link CTS 4.2.1.5, also avoiding the long AUX
> +		 * timeouts that would otherwise happen.
> +		 * TODO: abort the transfer on non-TC ports as well.
> +		 */
> +		if (!intel_tc_port_connected_locked(&dig_port->base)) {
> +			ret = -ENXIO;

TC port being a physical object this error code could be ENODEV as well, right?

Anyway, patch looks ok to me.

Reviewed-by: Mika Kahola <mika.kahola@intel.com>

> +			goto out_unlock;
> +		}
> +	}
> 
>  	aux_domain = intel_aux_power_domain(dig_port);
> 
> @@ -367,7 +378,7 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp,
> 
>  	intel_pps_unlock(intel_dp, pps_wakeref);
>  	intel_display_power_put_async(i915, aux_domain, aux_wakeref);
> -
> +out_unlock:
>  	if (is_tc_port)
>  		intel_tc_port_unlock(dig_port);
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_tc.c
> b/drivers/gpu/drm/i915/display/intel_tc.c
> index f45328712bff1..050f998284592 100644
> --- a/drivers/gpu/drm/i915/display/intel_tc.c
> +++ b/drivers/gpu/drm/i915/display/intel_tc.c
> @@ -768,16 +768,23 @@ void intel_tc_port_sanitize_mode(struct
> intel_digital_port *dig_port)
>   * connected ports are usable, and avoids exposing to the users objects they
>   * can't really use.
>   */
> +bool intel_tc_port_connected_locked(struct intel_encoder *encoder) {
> +	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
> +	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> +
> +	drm_WARN_ON(&i915->drm, !intel_tc_port_ref_held(dig_port));
> +
> +	return tc_port_live_status_mask(dig_port) & BIT(dig_port->tc_mode); }
> +
>  bool intel_tc_port_connected(struct intel_encoder *encoder)  {
>  	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
>  	bool is_connected;
> 
>  	intel_tc_port_lock(dig_port);
> -
> -	is_connected = tc_port_live_status_mask(dig_port) &
> -		       BIT(dig_port->tc_mode);
> -
> +	is_connected = intel_tc_port_connected_locked(encoder);
>  	intel_tc_port_unlock(dig_port);
> 
>  	return is_connected;
> diff --git a/drivers/gpu/drm/i915/display/intel_tc.h
> b/drivers/gpu/drm/i915/display/intel_tc.h
> index d54082e2d5e8d..93813056043a5 100644
> --- a/drivers/gpu/drm/i915/display/intel_tc.h
> +++ b/drivers/gpu/drm/i915/display/intel_tc.h
> @@ -17,6 +17,7 @@ bool intel_tc_port_in_dp_alt_mode(struct
> intel_digital_port *dig_port);  bool intel_tc_port_in_legacy_mode(struct
> intel_digital_port *dig_port);
> 
>  bool intel_tc_port_connected(struct intel_encoder *encoder);
> +bool intel_tc_port_connected_locked(struct intel_encoder *encoder);
> 
>  u32 intel_tc_port_get_lane_mask(struct intel_digital_port *dig_port);
>  u32 intel_tc_port_get_pin_assignment_mask(struct intel_digital_port
> *dig_port);
> --
> 2.37.1
Imre Deak March 21, 2023, 1:45 p.m. UTC | #2
On Tue, Mar 21, 2023 at 01:09:41PM +0200, Kahola, Mika wrote:
> > -----Original Message-----
> > From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of Imre
> > Deak
> > Sent: Thursday, March 16, 2023 3:17 PM
> > To: intel-gfx@lists.freedesktop.org
> > Cc: Chris Chiu <chris.chiu@canonical.com>
> > Subject: [Intel-gfx] [PATCH 01/14] drm/i915/tc: Abort DP AUX transfer on a
> > disconnected TC port
> >
> > On TC ports the 4ms AUX timeout combined with the 5 * 32 retry attempts
> > during DPCD accesses adds a 640ms delay to each access if the sink is
> > disconnected. This in turn slows down a modeset during which the sink is
> > disconnected (for instance a disabling modeset).
> >
> > Prevent the above delay by aborting AUX transfers on a TC port with a
> > disconnected sink.
> >
> > The DP 1.4a link CTS (4.2.1.5 Source Device Inactive HPD / Inactive AUX
> > Test") also requires not to initiate AUX transfers on disconnected DP ports in
> > general, however this patch doesn't change the behavior on non-TC ports,
> > leaving that for a follow-up.
> >
> > Reported-and-tested-by: Chris Chiu <chris.chiu@canonical.com>
> > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8279
> > Signed-off-by: Imre Deak <imre.deak@intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_dp_aux.c | 15 +++++++++++++--
> >  drivers/gpu/drm/i915/display/intel_tc.c     | 15 +++++++++++----
> >  drivers/gpu/drm/i915/display/intel_tc.h     |  1 +
> >  3 files changed, 25 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c
> > b/drivers/gpu/drm/i915/display/intel_dp_aux.c
> > index 96967e21c94c2..eb07dc5d87099 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c
> > @@ -205,8 +205,19 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp,
> >       for (i = 0; i < ARRAY_SIZE(ch_data); i++)
> >               ch_data[i] = intel_dp->aux_ch_data_reg(intel_dp, i);
> >
> > -     if (is_tc_port)
> > +     if (is_tc_port) {
> >               intel_tc_port_lock(dig_port);
> > +             /*
> > +              * Abort transfers on a disconnected port as required by
> > +              * DP 1.4a link CTS 4.2.1.5, also avoiding the long AUX
> > +              * timeouts that would otherwise happen.
> > +              * TODO: abort the transfer on non-TC ports as well.
> > +              */
> > +             if (!intel_tc_port_connected_locked(&dig_port->base)) {
> > +                     ret = -ENXIO;
> 
> TC port being a physical object this error code could be ENODEV as well, right?

The meaning of either error code is not defined precisely, but I
interpreted ENXIO as a - temporary - error/non-presence of the remote
device downstream of the port. There is another driver returning ENXIO
for the same case.

> Anyway, patch looks ok to me.
> 
> Reviewed-by: Mika Kahola <mika.kahola@intel.com>
> 
> > +                     goto out_unlock;
> > +             }
> > +     }
> >
> >       aux_domain = intel_aux_power_domain(dig_port);
> >
> > @@ -367,7 +378,7 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp,
> >
> >       intel_pps_unlock(intel_dp, pps_wakeref);
> >       intel_display_power_put_async(i915, aux_domain, aux_wakeref);
> > -
> > +out_unlock:
> >       if (is_tc_port)
> >               intel_tc_port_unlock(dig_port);
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_tc.c
> > b/drivers/gpu/drm/i915/display/intel_tc.c
> > index f45328712bff1..050f998284592 100644
> > --- a/drivers/gpu/drm/i915/display/intel_tc.c
> > +++ b/drivers/gpu/drm/i915/display/intel_tc.c
> > @@ -768,16 +768,23 @@ void intel_tc_port_sanitize_mode(struct
> > intel_digital_port *dig_port)
> >   * connected ports are usable, and avoids exposing to the users objects they
> >   * can't really use.
> >   */
> > +bool intel_tc_port_connected_locked(struct intel_encoder *encoder) {
> > +     struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
> > +     struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> > +
> > +     drm_WARN_ON(&i915->drm, !intel_tc_port_ref_held(dig_port));
> > +
> > +     return tc_port_live_status_mask(dig_port) & BIT(dig_port->tc_mode); }
> > +
> >  bool intel_tc_port_connected(struct intel_encoder *encoder)  {
> >       struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
> >       bool is_connected;
> >
> >       intel_tc_port_lock(dig_port);
> > -
> > -     is_connected = tc_port_live_status_mask(dig_port) &
> > -                    BIT(dig_port->tc_mode);
> > -
> > +     is_connected = intel_tc_port_connected_locked(encoder);
> >       intel_tc_port_unlock(dig_port);
> >
> >       return is_connected;
> > diff --git a/drivers/gpu/drm/i915/display/intel_tc.h
> > b/drivers/gpu/drm/i915/display/intel_tc.h
> > index d54082e2d5e8d..93813056043a5 100644
> > --- a/drivers/gpu/drm/i915/display/intel_tc.h
> > +++ b/drivers/gpu/drm/i915/display/intel_tc.h
> > @@ -17,6 +17,7 @@ bool intel_tc_port_in_dp_alt_mode(struct
> > intel_digital_port *dig_port);  bool intel_tc_port_in_legacy_mode(struct
> > intel_digital_port *dig_port);
> >
> >  bool intel_tc_port_connected(struct intel_encoder *encoder);
> > +bool intel_tc_port_connected_locked(struct intel_encoder *encoder);
> >
> >  u32 intel_tc_port_get_lane_mask(struct intel_digital_port *dig_port);
> >  u32 intel_tc_port_get_pin_assignment_mask(struct intel_digital_port
> > *dig_port);
> > --
> > 2.37.1
>
Andrzej Hajda March 22, 2023, 11:19 a.m. UTC | #3
On 16.03.2023 14:17, Imre Deak wrote:
> On TC ports the 4ms AUX timeout combined with the 5 * 32 retry
> attempts during DPCD accesses adds a 640ms delay to each access if the
> sink is disconnected. This in turn slows down a modeset during which the
> sink is disconnected (for instance a disabling modeset).
> 
> Prevent the above delay by aborting AUX transfers on a TC port with a
> disconnected sink.
> 
> The DP 1.4a link CTS (4.2.1.5 Source Device Inactive HPD / Inactive AUX
> Test") also requires not to initiate AUX transfers on disconnected DP
> ports in general, however this patch doesn't change the behavior on
> non-TC ports, leaving that for a follow-up.
> 
> Reported-and-tested-by: Chris Chiu <chris.chiu@canonical.com>
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8279
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> ---
>   drivers/gpu/drm/i915/display/intel_dp_aux.c | 15 +++++++++++++--
>   drivers/gpu/drm/i915/display/intel_tc.c     | 15 +++++++++++----
>   drivers/gpu/drm/i915/display/intel_tc.h     |  1 +
>   3 files changed, 25 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c
> index 96967e21c94c2..eb07dc5d87099 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c
> @@ -205,8 +205,19 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp,
>   	for (i = 0; i < ARRAY_SIZE(ch_data); i++)
>   		ch_data[i] = intel_dp->aux_ch_data_reg(intel_dp, i);
>   
> -	if (is_tc_port)
> +	if (is_tc_port) {
>   		intel_tc_port_lock(dig_port);
> +		/*
> +		 * Abort transfers on a disconnected port as required by
> +		 * DP 1.4a link CTS 4.2.1.5, also avoiding the long AUX
> +		 * timeouts that would otherwise happen.
> +		 * TODO: abort the transfer on non-TC ports as well.

Yes, for all ports this is definitely desirable, for example grep shows
about 15000 timeouts per one CI dmesg[1].

At least I hope, this cures the plague.

Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>

[1]: 
http://gfx-ci.igk.intel.com/tree/drm-tip/CI_DRM_12884/fi-elk-e7500/dmesg0.txt

Regards
Andrzej


> +		 */
> +		if (!intel_tc_port_connected_locked(&dig_port->base)) {
> +			ret = -ENXIO;
> +			goto out_unlock;
> +		}
> +	}
>   
>   	aux_domain = intel_aux_power_domain(dig_port);
>   
> @@ -367,7 +378,7 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp,
>   
>   	intel_pps_unlock(intel_dp, pps_wakeref);
>   	intel_display_power_put_async(i915, aux_domain, aux_wakeref);
> -
> +out_unlock:
>   	if (is_tc_port)
>   		intel_tc_port_unlock(dig_port);
>   
> diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c
> index f45328712bff1..050f998284592 100644
> --- a/drivers/gpu/drm/i915/display/intel_tc.c
> +++ b/drivers/gpu/drm/i915/display/intel_tc.c
> @@ -768,16 +768,23 @@ void intel_tc_port_sanitize_mode(struct intel_digital_port *dig_port)
>    * connected ports are usable, and avoids exposing to the users objects they
>    * can't really use.
>    */
> +bool intel_tc_port_connected_locked(struct intel_encoder *encoder)
> +{
> +	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
> +	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> +
> +	drm_WARN_ON(&i915->drm, !intel_tc_port_ref_held(dig_port));
> +
> +	return tc_port_live_status_mask(dig_port) & BIT(dig_port->tc_mode);
> +}
> +
>   bool intel_tc_port_connected(struct intel_encoder *encoder)
>   {
>   	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
>   	bool is_connected;
>   
>   	intel_tc_port_lock(dig_port);
> -
> -	is_connected = tc_port_live_status_mask(dig_port) &
> -		       BIT(dig_port->tc_mode);
> -
> +	is_connected = intel_tc_port_connected_locked(encoder);
>   	intel_tc_port_unlock(dig_port);
>   
>   	return is_connected;
> diff --git a/drivers/gpu/drm/i915/display/intel_tc.h b/drivers/gpu/drm/i915/display/intel_tc.h
> index d54082e2d5e8d..93813056043a5 100644
> --- a/drivers/gpu/drm/i915/display/intel_tc.h
> +++ b/drivers/gpu/drm/i915/display/intel_tc.h
> @@ -17,6 +17,7 @@ bool intel_tc_port_in_dp_alt_mode(struct intel_digital_port *dig_port);
>   bool intel_tc_port_in_legacy_mode(struct intel_digital_port *dig_port);
>   
>   bool intel_tc_port_connected(struct intel_encoder *encoder);
> +bool intel_tc_port_connected_locked(struct intel_encoder *encoder);
>   
>   u32 intel_tc_port_get_lane_mask(struct intel_digital_port *dig_port);
>   u32 intel_tc_port_get_pin_assignment_mask(struct intel_digital_port *dig_port);
Imre Deak March 22, 2023, 12:04 p.m. UTC | #4
On Wed, Mar 22, 2023 at 12:19:26PM +0100, Andrzej Hajda wrote:
> On 16.03.2023 14:17, Imre Deak wrote:
> > On TC ports the 4ms AUX timeout combined with the 5 * 32 retry
> > attempts during DPCD accesses adds a 640ms delay to each access if the
> > sink is disconnected. This in turn slows down a modeset during which the
> > sink is disconnected (for instance a disabling modeset).
> > 
> > Prevent the above delay by aborting AUX transfers on a TC port with a
> > disconnected sink.
> > 
> > The DP 1.4a link CTS (4.2.1.5 Source Device Inactive HPD / Inactive AUX
> > Test") also requires not to initiate AUX transfers on disconnected DP
> > ports in general, however this patch doesn't change the behavior on
> > non-TC ports, leaving that for a follow-up.
> > 
> > Reported-and-tested-by: Chris Chiu <chris.chiu@canonical.com>
> > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8279
> > Signed-off-by: Imre Deak <imre.deak@intel.com>
> > ---
> >   drivers/gpu/drm/i915/display/intel_dp_aux.c | 15 +++++++++++++--
> >   drivers/gpu/drm/i915/display/intel_tc.c     | 15 +++++++++++----
> >   drivers/gpu/drm/i915/display/intel_tc.h     |  1 +
> >   3 files changed, 25 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c
> > index 96967e21c94c2..eb07dc5d87099 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c
> > @@ -205,8 +205,19 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp,
> >   	for (i = 0; i < ARRAY_SIZE(ch_data); i++)
> >   		ch_data[i] = intel_dp->aux_ch_data_reg(intel_dp, i);
> > -	if (is_tc_port)
> > +	if (is_tc_port) {
> >   		intel_tc_port_lock(dig_port);
> > +		/*
> > +		 * Abort transfers on a disconnected port as required by
> > +		 * DP 1.4a link CTS 4.2.1.5, also avoiding the long AUX
> > +		 * timeouts that would otherwise happen.
> > +		 * TODO: abort the transfer on non-TC ports as well.
> 
> Yes, for all ports this is definitely desirable, for example grep shows
> about 15000 timeouts per one CI dmesg[1].
> 
> At least I hope, this cures the plague.

Looks like a different scenario where HDMI and DP share the same HPD
pin.

> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>

Thanks.

> 
> [1]:
> http://gfx-ci.igk.intel.com/tree/drm-tip/CI_DRM_12884/fi-elk-e7500/dmesg0.txt
> 
> Regards
> Andrzej
> 
> 
> > +		 */
> > +		if (!intel_tc_port_connected_locked(&dig_port->base)) {
> > +			ret = -ENXIO;
> > +			goto out_unlock;
> > +		}
> > +	}
> >   	aux_domain = intel_aux_power_domain(dig_port);
> > @@ -367,7 +378,7 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp,
> >   	intel_pps_unlock(intel_dp, pps_wakeref);
> >   	intel_display_power_put_async(i915, aux_domain, aux_wakeref);
> > -
> > +out_unlock:
> >   	if (is_tc_port)
> >   		intel_tc_port_unlock(dig_port);
> > diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c
> > index f45328712bff1..050f998284592 100644
> > --- a/drivers/gpu/drm/i915/display/intel_tc.c
> > +++ b/drivers/gpu/drm/i915/display/intel_tc.c
> > @@ -768,16 +768,23 @@ void intel_tc_port_sanitize_mode(struct intel_digital_port *dig_port)
> >    * connected ports are usable, and avoids exposing to the users objects they
> >    * can't really use.
> >    */
> > +bool intel_tc_port_connected_locked(struct intel_encoder *encoder)
> > +{
> > +	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
> > +	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> > +
> > +	drm_WARN_ON(&i915->drm, !intel_tc_port_ref_held(dig_port));
> > +
> > +	return tc_port_live_status_mask(dig_port) & BIT(dig_port->tc_mode);
> > +}
> > +
> >   bool intel_tc_port_connected(struct intel_encoder *encoder)
> >   {
> >   	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
> >   	bool is_connected;
> >   	intel_tc_port_lock(dig_port);
> > -
> > -	is_connected = tc_port_live_status_mask(dig_port) &
> > -		       BIT(dig_port->tc_mode);
> > -
> > +	is_connected = intel_tc_port_connected_locked(encoder);
> >   	intel_tc_port_unlock(dig_port);
> >   	return is_connected;
> > diff --git a/drivers/gpu/drm/i915/display/intel_tc.h b/drivers/gpu/drm/i915/display/intel_tc.h
> > index d54082e2d5e8d..93813056043a5 100644
> > --- a/drivers/gpu/drm/i915/display/intel_tc.h
> > +++ b/drivers/gpu/drm/i915/display/intel_tc.h
> > @@ -17,6 +17,7 @@ bool intel_tc_port_in_dp_alt_mode(struct intel_digital_port *dig_port);
> >   bool intel_tc_port_in_legacy_mode(struct intel_digital_port *dig_port);
> >   bool intel_tc_port_connected(struct intel_encoder *encoder);
> > +bool intel_tc_port_connected_locked(struct intel_encoder *encoder);
> >   u32 intel_tc_port_get_lane_mask(struct intel_digital_port *dig_port);
> >   u32 intel_tc_port_get_pin_assignment_mask(struct intel_digital_port *dig_port);
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c
index 96967e21c94c2..eb07dc5d87099 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c
@@ -205,8 +205,19 @@  intel_dp_aux_xfer(struct intel_dp *intel_dp,
 	for (i = 0; i < ARRAY_SIZE(ch_data); i++)
 		ch_data[i] = intel_dp->aux_ch_data_reg(intel_dp, i);
 
-	if (is_tc_port)
+	if (is_tc_port) {
 		intel_tc_port_lock(dig_port);
+		/*
+		 * Abort transfers on a disconnected port as required by
+		 * DP 1.4a link CTS 4.2.1.5, also avoiding the long AUX
+		 * timeouts that would otherwise happen.
+		 * TODO: abort the transfer on non-TC ports as well.
+		 */
+		if (!intel_tc_port_connected_locked(&dig_port->base)) {
+			ret = -ENXIO;
+			goto out_unlock;
+		}
+	}
 
 	aux_domain = intel_aux_power_domain(dig_port);
 
@@ -367,7 +378,7 @@  intel_dp_aux_xfer(struct intel_dp *intel_dp,
 
 	intel_pps_unlock(intel_dp, pps_wakeref);
 	intel_display_power_put_async(i915, aux_domain, aux_wakeref);
-
+out_unlock:
 	if (is_tc_port)
 		intel_tc_port_unlock(dig_port);
 
diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c
index f45328712bff1..050f998284592 100644
--- a/drivers/gpu/drm/i915/display/intel_tc.c
+++ b/drivers/gpu/drm/i915/display/intel_tc.c
@@ -768,16 +768,23 @@  void intel_tc_port_sanitize_mode(struct intel_digital_port *dig_port)
  * connected ports are usable, and avoids exposing to the users objects they
  * can't really use.
  */
+bool intel_tc_port_connected_locked(struct intel_encoder *encoder)
+{
+	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
+	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
+
+	drm_WARN_ON(&i915->drm, !intel_tc_port_ref_held(dig_port));
+
+	return tc_port_live_status_mask(dig_port) & BIT(dig_port->tc_mode);
+}
+
 bool intel_tc_port_connected(struct intel_encoder *encoder)
 {
 	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
 	bool is_connected;
 
 	intel_tc_port_lock(dig_port);
-
-	is_connected = tc_port_live_status_mask(dig_port) &
-		       BIT(dig_port->tc_mode);
-
+	is_connected = intel_tc_port_connected_locked(encoder);
 	intel_tc_port_unlock(dig_port);
 
 	return is_connected;
diff --git a/drivers/gpu/drm/i915/display/intel_tc.h b/drivers/gpu/drm/i915/display/intel_tc.h
index d54082e2d5e8d..93813056043a5 100644
--- a/drivers/gpu/drm/i915/display/intel_tc.h
+++ b/drivers/gpu/drm/i915/display/intel_tc.h
@@ -17,6 +17,7 @@  bool intel_tc_port_in_dp_alt_mode(struct intel_digital_port *dig_port);
 bool intel_tc_port_in_legacy_mode(struct intel_digital_port *dig_port);
 
 bool intel_tc_port_connected(struct intel_encoder *encoder);
+bool intel_tc_port_connected_locked(struct intel_encoder *encoder);
 
 u32 intel_tc_port_get_lane_mask(struct intel_digital_port *dig_port);
 u32 intel_tc_port_get_pin_assignment_mask(struct intel_digital_port *dig_port);