diff mbox

[1/3] drm/i915: Check pixel rate for DP to VGA dongle

Message ID 1462275998-4864-2-git-send-email-mika.kahola@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Kahola, Mika May 3, 2016, 11:46 a.m. UTC
Prep work to improve DP branch device handling.

Filter out a mode that exceeds the max pixel rate setting
for DP to VGA dongle. This is defined in DPCD register 0x81
if detailed cap info i.e. info field is 4 bytes long and
it is available for DP downstream port.

The register defines the pixel rate divided by 8 in MP/s.

Signed-off-by: Mika Kahola <mika.kahola@intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c  | 34 ++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h |  9 +++++++++
 2 files changed, 43 insertions(+)

Comments

Ville Syrjälä May 3, 2016, 1:23 p.m. UTC | #1
On Tue, May 03, 2016 at 02:46:36PM +0300, Mika Kahola wrote:
> Prep work to improve DP branch device handling.
> 
> Filter out a mode that exceeds the max pixel rate setting
> for DP to VGA dongle. This is defined in DPCD register 0x81
> if detailed cap info i.e. info field is 4 bytes long and
> it is available for DP downstream port.
> 
> The register defines the pixel rate divided by 8 in MP/s.
> 
> Signed-off-by: Mika Kahola <mika.kahola@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dp.c  | 34 ++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_drv.h |  9 +++++++++
>  2 files changed, 43 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 3633002..74a04ce 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -201,6 +201,13 @@ intel_dp_mode_valid(struct drm_connector *connector,
>  	int max_rate, mode_rate, max_lanes, max_link_clock;
>  	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
>  
> +	/* DP to VGA dongle may define max pixel rate in DPCD */
> +	if (intel_dp->dfp.present &&
> +	    intel_dp->dfp.detailed_cap_info &&
> +	    (intel_dp->dfp.type & DP_DS_PORT_TYPE_VGA) &&
> +	    (intel_dp->dfp.dot_clk > 0))
> +		max_dotclk = min(max_dotclk, intel_dp->dfp.dot_clk);

What's dfp?

Looks like most of this stuff is not really needed. Just storing a max
dotclock per downstream port would seem to suffice.

> +
>  	if (is_edp(intel_dp) && fixed_mode) {
>  		if (mode->hdisplay > fixed_mode->hdisplay)
>  			return MODE_PANEL;
> @@ -4566,6 +4573,28 @@ static const struct drm_encoder_funcs intel_dp_enc_funcs = {
>  	.destroy = intel_dp_encoder_destroy,
>  };
>  
> +static void intel_dp_get_dfp(struct intel_dp *intel_dp)
> +{
> +	uint8_t dfp_info[4];
> +
> +	intel_dp->dfp.detailed_cap_info = intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE;
> +
> +	if (drm_dp_dpcd_read(&intel_dp->aux, DP_DOWNSTREAM_PORT_0, dfp_info, 4) < 0) {
> +		intel_dp->dfp.present = false;
> +		intel_dp->dfp.detailed_cap_info = false;
> +		return; /* aux transfer failed */
> +	}
> +
> +	intel_dp->dfp.type = dfp_info[0] & DP_DS_PORT_TYPE_MASK;
> +
> +	if (intel_dp->dfp.detailed_cap_info) {
> +		if (intel_dp->dfp.type & DP_DS_PORT_TYPE_VGA) {
> +			intel_dp->dfp.dot_clk = dfp_info[1] * 8 * 1000;
> +			DRM_DEBUG_KMS("max pixel rate for VGA is %d kHz\n", intel_dp->dfp.dot_clk);
> +		}

I would suggest putting this sort of stuff into the dp helper. I once
started to hatch something to deal with these downstream port limits,
but never finished it. I pushed my WIP stuff (mostly ideas how to parse
these port caps) to 

git://github.com/vsyrjala/linux.git dp_downstream_ports

maybe you can to see if there's anything useful for you there.

> +	}
> +}
> +
>  enum irqreturn
>  intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
>  {
> @@ -4599,6 +4628,11 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
>  	power_domain = intel_display_port_aux_power_domain(intel_encoder);
>  	intel_display_power_get(dev_priv, power_domain);
>  
> +	intel_dp->dfp.present = intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] & 0x1;
> +
> +	if (intel_dp->dfp.present)
> +		intel_dp_get_dfp(intel_dp);
> +
>  	if (long_hpd) {
>  		/* indicate that we need to restart link training */
>  		intel_dp->train_set_valid = false;
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 21dee3f..9798a59 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -794,6 +794,13 @@ enum link_m_n_set {
>  	M2_N2
>  };
>  
> +struct intel_dp_dfp {
> +	bool present;
> +	int type;
> +	bool detailed_cap_info;
> +	int dot_clk; /* pixel rate for VGA dongles */
> +};
> +
>  struct intel_dp {
>  	i915_reg_t output_reg;
>  	i915_reg_t aux_ch_ctl_reg;
> @@ -861,6 +868,8 @@ struct intel_dp {
>  
>  	bool train_set_valid;
>  
> +	struct intel_dp_dfp dfp;
> +
>  	/* Displayport compliance testing */
>  	unsigned long compliance_test_type;
>  	unsigned long compliance_test_data;
> -- 
> 1.9.1
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Daniel Vetter May 3, 2016, 2:28 p.m. UTC | #2
On Tue, May 03, 2016 at 04:23:34PM +0300, Ville Syrjälä wrote:
> On Tue, May 03, 2016 at 02:46:36PM +0300, Mika Kahola wrote:
> > Prep work to improve DP branch device handling.
> > 
> > Filter out a mode that exceeds the max pixel rate setting
> > for DP to VGA dongle. This is defined in DPCD register 0x81
> > if detailed cap info i.e. info field is 4 bytes long and
> > it is available for DP downstream port.
> > 
> > The register defines the pixel rate divided by 8 in MP/s.
> > 
> > Signed-off-by: Mika Kahola <mika.kahola@intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_dp.c  | 34 ++++++++++++++++++++++++++++++++++
> >  drivers/gpu/drm/i915/intel_drv.h |  9 +++++++++
> >  2 files changed, 43 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > index 3633002..74a04ce 100644
> > --- a/drivers/gpu/drm/i915/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > @@ -201,6 +201,13 @@ intel_dp_mode_valid(struct drm_connector *connector,
> >  	int max_rate, mode_rate, max_lanes, max_link_clock;
> >  	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
> >  
> > +	/* DP to VGA dongle may define max pixel rate in DPCD */
> > +	if (intel_dp->dfp.present &&
> > +	    intel_dp->dfp.detailed_cap_info &&
> > +	    (intel_dp->dfp.type & DP_DS_PORT_TYPE_VGA) &&
> > +	    (intel_dp->dfp.dot_clk > 0))
> > +		max_dotclk = min(max_dotclk, intel_dp->dfp.dot_clk);
> 
> What's dfp?
> 
> Looks like most of this stuff is not really needed. Just storing a max
> dotclock per downstream port would seem to suffice.
> 
> > +
> >  	if (is_edp(intel_dp) && fixed_mode) {
> >  		if (mode->hdisplay > fixed_mode->hdisplay)
> >  			return MODE_PANEL;
> > @@ -4566,6 +4573,28 @@ static const struct drm_encoder_funcs intel_dp_enc_funcs = {
> >  	.destroy = intel_dp_encoder_destroy,
> >  };
> >  
> > +static void intel_dp_get_dfp(struct intel_dp *intel_dp)
> > +{
> > +	uint8_t dfp_info[4];
> > +
> > +	intel_dp->dfp.detailed_cap_info = intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE;
> > +
> > +	if (drm_dp_dpcd_read(&intel_dp->aux, DP_DOWNSTREAM_PORT_0, dfp_info, 4) < 0) {
> > +		intel_dp->dfp.present = false;
> > +		intel_dp->dfp.detailed_cap_info = false;
> > +		return; /* aux transfer failed */
> > +	}
> > +
> > +	intel_dp->dfp.type = dfp_info[0] & DP_DS_PORT_TYPE_MASK;
> > +
> > +	if (intel_dp->dfp.detailed_cap_info) {
> > +		if (intel_dp->dfp.type & DP_DS_PORT_TYPE_VGA) {
> > +			intel_dp->dfp.dot_clk = dfp_info[1] * 8 * 1000;
> > +			DRM_DEBUG_KMS("max pixel rate for VGA is %d kHz\n", intel_dp->dfp.dot_clk);
> > +		}
> 
> I would suggest putting this sort of stuff into the dp helper. I once
> started to hatch something to deal with these downstream port limits,
> but never finished it. I pushed my WIP stuff (mostly ideas how to parse
> these port caps) to 
> 
> git://github.com/vsyrjala/linux.git dp_downstream_ports
> 
> maybe you can to see if there's anything useful for you there.

Seconded on at least moving the computation into the dp helpers. i915.ko
really should only ask the helpers for the final result, maybe with an
intermediate step to cache the dp aux register stuff. There's already some
structures in the dp helpers to store sink state, we could start using
those (unfortunately they're not agreeing on what the canonical one should
be).
-Daniel

> 
> > +	}
> > +}
> > +
> >  enum irqreturn
> >  intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
> >  {
> > @@ -4599,6 +4628,11 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
> >  	power_domain = intel_display_port_aux_power_domain(intel_encoder);
> >  	intel_display_power_get(dev_priv, power_domain);
> >  
> > +	intel_dp->dfp.present = intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] & 0x1;
> > +
> > +	if (intel_dp->dfp.present)
> > +		intel_dp_get_dfp(intel_dp);
> > +
> >  	if (long_hpd) {
> >  		/* indicate that we need to restart link training */
> >  		intel_dp->train_set_valid = false;
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > index 21dee3f..9798a59 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -794,6 +794,13 @@ enum link_m_n_set {
> >  	M2_N2
> >  };
> >  
> > +struct intel_dp_dfp {
> > +	bool present;
> > +	int type;
> > +	bool detailed_cap_info;
> > +	int dot_clk; /* pixel rate for VGA dongles */
> > +};
> > +
> >  struct intel_dp {
> >  	i915_reg_t output_reg;
> >  	i915_reg_t aux_ch_ctl_reg;
> > @@ -861,6 +868,8 @@ struct intel_dp {
> >  
> >  	bool train_set_valid;
> >  
> > +	struct intel_dp_dfp dfp;
> > +
> >  	/* Displayport compliance testing */
> >  	unsigned long compliance_test_type;
> >  	unsigned long compliance_test_data;
> > -- 
> > 1.9.1
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Ville Syrjälä
> Intel OTC
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Ville Syrjälä May 3, 2016, 2:33 p.m. UTC | #3
On Tue, May 03, 2016 at 04:28:00PM +0200, Daniel Vetter wrote:
> On Tue, May 03, 2016 at 04:23:34PM +0300, Ville Syrjälä wrote:
> > On Tue, May 03, 2016 at 02:46:36PM +0300, Mika Kahola wrote:
> > > Prep work to improve DP branch device handling.
> > > 
> > > Filter out a mode that exceeds the max pixel rate setting
> > > for DP to VGA dongle. This is defined in DPCD register 0x81
> > > if detailed cap info i.e. info field is 4 bytes long and
> > > it is available for DP downstream port.
> > > 
> > > The register defines the pixel rate divided by 8 in MP/s.
> > > 
> > > Signed-off-by: Mika Kahola <mika.kahola@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/intel_dp.c  | 34 ++++++++++++++++++++++++++++++++++
> > >  drivers/gpu/drm/i915/intel_drv.h |  9 +++++++++
> > >  2 files changed, 43 insertions(+)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > > index 3633002..74a04ce 100644
> > > --- a/drivers/gpu/drm/i915/intel_dp.c
> > > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > > @@ -201,6 +201,13 @@ intel_dp_mode_valid(struct drm_connector *connector,
> > >  	int max_rate, mode_rate, max_lanes, max_link_clock;
> > >  	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
> > >  
> > > +	/* DP to VGA dongle may define max pixel rate in DPCD */
> > > +	if (intel_dp->dfp.present &&
> > > +	    intel_dp->dfp.detailed_cap_info &&
> > > +	    (intel_dp->dfp.type & DP_DS_PORT_TYPE_VGA) &&
> > > +	    (intel_dp->dfp.dot_clk > 0))
> > > +		max_dotclk = min(max_dotclk, intel_dp->dfp.dot_clk);
> > 
> > What's dfp?
> > 
> > Looks like most of this stuff is not really needed. Just storing a max
> > dotclock per downstream port would seem to suffice.
> > 
> > > +
> > >  	if (is_edp(intel_dp) && fixed_mode) {
> > >  		if (mode->hdisplay > fixed_mode->hdisplay)
> > >  			return MODE_PANEL;
> > > @@ -4566,6 +4573,28 @@ static const struct drm_encoder_funcs intel_dp_enc_funcs = {
> > >  	.destroy = intel_dp_encoder_destroy,
> > >  };
> > >  
> > > +static void intel_dp_get_dfp(struct intel_dp *intel_dp)
> > > +{
> > > +	uint8_t dfp_info[4];
> > > +
> > > +	intel_dp->dfp.detailed_cap_info = intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE;
> > > +
> > > +	if (drm_dp_dpcd_read(&intel_dp->aux, DP_DOWNSTREAM_PORT_0, dfp_info, 4) < 0) {
> > > +		intel_dp->dfp.present = false;
> > > +		intel_dp->dfp.detailed_cap_info = false;
> > > +		return; /* aux transfer failed */
> > > +	}
> > > +
> > > +	intel_dp->dfp.type = dfp_info[0] & DP_DS_PORT_TYPE_MASK;
> > > +
> > > +	if (intel_dp->dfp.detailed_cap_info) {
> > > +		if (intel_dp->dfp.type & DP_DS_PORT_TYPE_VGA) {
> > > +			intel_dp->dfp.dot_clk = dfp_info[1] * 8 * 1000;
> > > +			DRM_DEBUG_KMS("max pixel rate for VGA is %d kHz\n", intel_dp->dfp.dot_clk);
> > > +		}
> > 
> > I would suggest putting this sort of stuff into the dp helper. I once
> > started to hatch something to deal with these downstream port limits,
> > but never finished it. I pushed my WIP stuff (mostly ideas how to parse
> > these port caps) to 
> > 
> > git://github.com/vsyrjala/linux.git dp_downstream_ports
> > 
> > maybe you can to see if there's anything useful for you there.
> 
> Seconded on at least moving the computation into the dp helpers. i915.ko
> really should only ask the helpers for the final result, maybe with an
> intermediate step to cache the dp aux register stuff. There's already some
> structures in the dp helpers to store sink state, we could start using
> those (unfortunately they're not agreeing on what the canonical one should
> be).

Yeah that thing is a bit of mess right now. As usual, I have a branch to
clean some of it up a bit. Mainly aiming to respect the sink HDMI TMDS
clock limits better. But I need to get the DP++ stuff landed before
I continue with that.
Kahola, Mika May 10, 2016, 9:44 a.m. UTC | #4
On Tue, 2016-05-03 at 16:28 +0200, Daniel Vetter wrote:
> On Tue, May 03, 2016 at 04:23:34PM +0300, Ville Syrjälä wrote:
> > On Tue, May 03, 2016 at 02:46:36PM +0300, Mika Kahola wrote:
> > > Prep work to improve DP branch device handling.
> > > 
> > > Filter out a mode that exceeds the max pixel rate setting
> > > for DP to VGA dongle. This is defined in DPCD register 0x81
> > > if detailed cap info i.e. info field is 4 bytes long and
> > > it is available for DP downstream port.
> > > 
> > > The register defines the pixel rate divided by 8 in MP/s.
> > > 
> > > Signed-off-by: Mika Kahola <mika.kahola@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/intel_dp.c  | 34 ++++++++++++++++++++++++++++++++++
> > >  drivers/gpu/drm/i915/intel_drv.h |  9 +++++++++
> > >  2 files changed, 43 insertions(+)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > > index 3633002..74a04ce 100644
> > > --- a/drivers/gpu/drm/i915/intel_dp.c
> > > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > > @@ -201,6 +201,13 @@ intel_dp_mode_valid(struct drm_connector *connector,
> > >  	int max_rate, mode_rate, max_lanes, max_link_clock;
> > >  	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
> > >  
> > > +	/* DP to VGA dongle may define max pixel rate in DPCD */
> > > +	if (intel_dp->dfp.present &&
> > > +	    intel_dp->dfp.detailed_cap_info &&
> > > +	    (intel_dp->dfp.type & DP_DS_PORT_TYPE_VGA) &&
> > > +	    (intel_dp->dfp.dot_clk > 0))
> > > +		max_dotclk = min(max_dotclk, intel_dp->dfp.dot_clk);
> > 
> > What's dfp?

dfp - Downstream-Facing Port
> > 
> > Looks like most of this stuff is not really needed. Just storing a max
> > dotclock per downstream port would seem to suffice.
> > 
> > > +
> > >  	if (is_edp(intel_dp) && fixed_mode) {
> > >  		if (mode->hdisplay > fixed_mode->hdisplay)
> > >  			return MODE_PANEL;
> > > @@ -4566,6 +4573,28 @@ static const struct drm_encoder_funcs intel_dp_enc_funcs = {
> > >  	.destroy = intel_dp_encoder_destroy,
> > >  };
> > >  
> > > +static void intel_dp_get_dfp(struct intel_dp *intel_dp)
> > > +{
> > > +	uint8_t dfp_info[4];
> > > +
> > > +	intel_dp->dfp.detailed_cap_info = intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE;
> > > +
> > > +	if (drm_dp_dpcd_read(&intel_dp->aux, DP_DOWNSTREAM_PORT_0, dfp_info, 4) < 0) {
> > > +		intel_dp->dfp.present = false;
> > > +		intel_dp->dfp.detailed_cap_info = false;
> > > +		return; /* aux transfer failed */
> > > +	}
> > > +
> > > +	intel_dp->dfp.type = dfp_info[0] & DP_DS_PORT_TYPE_MASK;
> > > +
> > > +	if (intel_dp->dfp.detailed_cap_info) {
> > > +		if (intel_dp->dfp.type & DP_DS_PORT_TYPE_VGA) {
> > > +			intel_dp->dfp.dot_clk = dfp_info[1] * 8 * 1000;
> > > +			DRM_DEBUG_KMS("max pixel rate for VGA is %d kHz\n", intel_dp->dfp.dot_clk);
> > > +		}
> > 
> > I would suggest putting this sort of stuff into the dp helper. I once
> > started to hatch something to deal with these downstream port limits,
> > but never finished it. I pushed my WIP stuff (mostly ideas how to parse
> > these port caps) to 
> > 
> > git://github.com/vsyrjala/linux.git dp_downstream_ports
> > 
> > maybe you can to see if there's anything useful for you there.
> 
> Seconded on at least moving the computation into the dp helpers. i915.ko
> really should only ask the helpers for the final result, maybe with an
> intermediate step to cache the dp aux register stuff. There's already some
> structures in the dp helpers to store sink state, we could start using
> those (unfortunately they're not agreeing on what the canonical one should
> be).
> -Daniel

Ok. Two votes for moving this stuff into the dp helpers. I'll do a
respin with this one. 

Cheers,
Mika

> 
> > 
> > > +	}
> > > +}
> > > +
> > >  enum irqreturn
> > >  intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
> > >  {
> > > @@ -4599,6 +4628,11 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
> > >  	power_domain = intel_display_port_aux_power_domain(intel_encoder);
> > >  	intel_display_power_get(dev_priv, power_domain);
> > >  
> > > +	intel_dp->dfp.present = intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] & 0x1;
> > > +
> > > +	if (intel_dp->dfp.present)
> > > +		intel_dp_get_dfp(intel_dp);
> > > +
> > >  	if (long_hpd) {
> > >  		/* indicate that we need to restart link training */
> > >  		intel_dp->train_set_valid = false;
> > > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > > index 21dee3f..9798a59 100644
> > > --- a/drivers/gpu/drm/i915/intel_drv.h
> > > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > > @@ -794,6 +794,13 @@ enum link_m_n_set {
> > >  	M2_N2
> > >  };
> > >  
> > > +struct intel_dp_dfp {
> > > +	bool present;
> > > +	int type;
> > > +	bool detailed_cap_info;
> > > +	int dot_clk; /* pixel rate for VGA dongles */
> > > +};
> > > +
> > >  struct intel_dp {
> > >  	i915_reg_t output_reg;
> > >  	i915_reg_t aux_ch_ctl_reg;
> > > @@ -861,6 +868,8 @@ struct intel_dp {
> > >  
> > >  	bool train_set_valid;
> > >  
> > > +	struct intel_dp_dfp dfp;
> > > +
> > >  	/* Displayport compliance testing */
> > >  	unsigned long compliance_test_type;
> > >  	unsigned long compliance_test_data;
> > > -- 
> > > 1.9.1
> > > 
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx@lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > 
> > -- 
> > Ville Syrjälä
> > Intel OTC
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
Ville Syrjälä May 10, 2016, 9:54 a.m. UTC | #5
On Tue, May 10, 2016 at 12:44:22PM +0300, Mika Kahola wrote:
> On Tue, 2016-05-03 at 16:28 +0200, Daniel Vetter wrote:
> > On Tue, May 03, 2016 at 04:23:34PM +0300, Ville Syrjälä wrote:
> > > On Tue, May 03, 2016 at 02:46:36PM +0300, Mika Kahola wrote:
> > > > Prep work to improve DP branch device handling.
> > > > 
> > > > Filter out a mode that exceeds the max pixel rate setting
> > > > for DP to VGA dongle. This is defined in DPCD register 0x81
> > > > if detailed cap info i.e. info field is 4 bytes long and
> > > > it is available for DP downstream port.
> > > > 
> > > > The register defines the pixel rate divided by 8 in MP/s.
> > > > 
> > > > Signed-off-by: Mika Kahola <mika.kahola@intel.com>
> > > > ---
> > > >  drivers/gpu/drm/i915/intel_dp.c  | 34 ++++++++++++++++++++++++++++++++++
> > > >  drivers/gpu/drm/i915/intel_drv.h |  9 +++++++++
> > > >  2 files changed, 43 insertions(+)
> > > > 
> > > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > > > index 3633002..74a04ce 100644
> > > > --- a/drivers/gpu/drm/i915/intel_dp.c
> > > > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > > > @@ -201,6 +201,13 @@ intel_dp_mode_valid(struct drm_connector *connector,
> > > >  	int max_rate, mode_rate, max_lanes, max_link_clock;
> > > >  	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
> > > >  
> > > > +	/* DP to VGA dongle may define max pixel rate in DPCD */
> > > > +	if (intel_dp->dfp.present &&
> > > > +	    intel_dp->dfp.detailed_cap_info &&
> > > > +	    (intel_dp->dfp.type & DP_DS_PORT_TYPE_VGA) &&
> > > > +	    (intel_dp->dfp.dot_clk > 0))
> > > > +		max_dotclk = min(max_dotclk, intel_dp->dfp.dot_clk);
> > > 
> > > What's dfp?
> 
> dfp - Downstream-Facing Port

I thought "digital flat panel" (as in the DFP standard and whatnot),
which was a bit confusing. So a bit of an overloaded TLA that one.
If we need such a substruct I might just call it downstream_port
or something along those lines.

> > > 
> > > Looks like most of this stuff is not really needed. Just storing a max
> > > dotclock per downstream port would seem to suffice.
> > > 
> > > > +
> > > >  	if (is_edp(intel_dp) && fixed_mode) {
> > > >  		if (mode->hdisplay > fixed_mode->hdisplay)
> > > >  			return MODE_PANEL;
> > > > @@ -4566,6 +4573,28 @@ static const struct drm_encoder_funcs intel_dp_enc_funcs = {
> > > >  	.destroy = intel_dp_encoder_destroy,
> > > >  };
> > > >  
> > > > +static void intel_dp_get_dfp(struct intel_dp *intel_dp)
> > > > +{
> > > > +	uint8_t dfp_info[4];
> > > > +
> > > > +	intel_dp->dfp.detailed_cap_info = intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE;
> > > > +
> > > > +	if (drm_dp_dpcd_read(&intel_dp->aux, DP_DOWNSTREAM_PORT_0, dfp_info, 4) < 0) {
> > > > +		intel_dp->dfp.present = false;
> > > > +		intel_dp->dfp.detailed_cap_info = false;
> > > > +		return; /* aux transfer failed */
> > > > +	}
> > > > +
> > > > +	intel_dp->dfp.type = dfp_info[0] & DP_DS_PORT_TYPE_MASK;
> > > > +
> > > > +	if (intel_dp->dfp.detailed_cap_info) {
> > > > +		if (intel_dp->dfp.type & DP_DS_PORT_TYPE_VGA) {
> > > > +			intel_dp->dfp.dot_clk = dfp_info[1] * 8 * 1000;
> > > > +			DRM_DEBUG_KMS("max pixel rate for VGA is %d kHz\n", intel_dp->dfp.dot_clk);
> > > > +		}
> > > 
> > > I would suggest putting this sort of stuff into the dp helper. I once
> > > started to hatch something to deal with these downstream port limits,
> > > but never finished it. I pushed my WIP stuff (mostly ideas how to parse
> > > these port caps) to 
> > > 
> > > git://github.com/vsyrjala/linux.git dp_downstream_ports
> > > 
> > > maybe you can to see if there's anything useful for you there.
> > 
> > Seconded on at least moving the computation into the dp helpers. i915.ko
> > really should only ask the helpers for the final result, maybe with an
> > intermediate step to cache the dp aux register stuff. There's already some
> > structures in the dp helpers to store sink state, we could start using
> > those (unfortunately they're not agreeing on what the canonical one should
> > be).
> > -Daniel
> 
> Ok. Two votes for moving this stuff into the dp helpers. I'll do a
> respin with this one. 
> 
> Cheers,
> Mika
> 
> > 
> > > 
> > > > +	}
> > > > +}
> > > > +
> > > >  enum irqreturn
> > > >  intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
> > > >  {
> > > > @@ -4599,6 +4628,11 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
> > > >  	power_domain = intel_display_port_aux_power_domain(intel_encoder);
> > > >  	intel_display_power_get(dev_priv, power_domain);
> > > >  
> > > > +	intel_dp->dfp.present = intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] & 0x1;
> > > > +
> > > > +	if (intel_dp->dfp.present)
> > > > +		intel_dp_get_dfp(intel_dp);
> > > > +
> > > >  	if (long_hpd) {
> > > >  		/* indicate that we need to restart link training */
> > > >  		intel_dp->train_set_valid = false;
> > > > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > > > index 21dee3f..9798a59 100644
> > > > --- a/drivers/gpu/drm/i915/intel_drv.h
> > > > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > > > @@ -794,6 +794,13 @@ enum link_m_n_set {
> > > >  	M2_N2
> > > >  };
> > > >  
> > > > +struct intel_dp_dfp {
> > > > +	bool present;
> > > > +	int type;
> > > > +	bool detailed_cap_info;
> > > > +	int dot_clk; /* pixel rate for VGA dongles */
> > > > +};
> > > > +
> > > >  struct intel_dp {
> > > >  	i915_reg_t output_reg;
> > > >  	i915_reg_t aux_ch_ctl_reg;
> > > > @@ -861,6 +868,8 @@ struct intel_dp {
> > > >  
> > > >  	bool train_set_valid;
> > > >  
> > > > +	struct intel_dp_dfp dfp;
> > > > +
> > > >  	/* Displayport compliance testing */
> > > >  	unsigned long compliance_test_type;
> > > >  	unsigned long compliance_test_data;
> > > > -- 
> > > > 1.9.1
> > > > 
> > > > _______________________________________________
> > > > Intel-gfx mailing list
> > > > Intel-gfx@lists.freedesktop.org
> > > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > > 
> > > -- 
> > > Ville Syrjälä
> > > Intel OTC
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx@lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > 
> 
> -- 
> Mika Kahola - Intel OTC
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 3633002..74a04ce 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -201,6 +201,13 @@  intel_dp_mode_valid(struct drm_connector *connector,
 	int max_rate, mode_rate, max_lanes, max_link_clock;
 	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
 
+	/* DP to VGA dongle may define max pixel rate in DPCD */
+	if (intel_dp->dfp.present &&
+	    intel_dp->dfp.detailed_cap_info &&
+	    (intel_dp->dfp.type & DP_DS_PORT_TYPE_VGA) &&
+	    (intel_dp->dfp.dot_clk > 0))
+		max_dotclk = min(max_dotclk, intel_dp->dfp.dot_clk);
+
 	if (is_edp(intel_dp) && fixed_mode) {
 		if (mode->hdisplay > fixed_mode->hdisplay)
 			return MODE_PANEL;
@@ -4566,6 +4573,28 @@  static const struct drm_encoder_funcs intel_dp_enc_funcs = {
 	.destroy = intel_dp_encoder_destroy,
 };
 
+static void intel_dp_get_dfp(struct intel_dp *intel_dp)
+{
+	uint8_t dfp_info[4];
+
+	intel_dp->dfp.detailed_cap_info = intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE;
+
+	if (drm_dp_dpcd_read(&intel_dp->aux, DP_DOWNSTREAM_PORT_0, dfp_info, 4) < 0) {
+		intel_dp->dfp.present = false;
+		intel_dp->dfp.detailed_cap_info = false;
+		return; /* aux transfer failed */
+	}
+
+	intel_dp->dfp.type = dfp_info[0] & DP_DS_PORT_TYPE_MASK;
+
+	if (intel_dp->dfp.detailed_cap_info) {
+		if (intel_dp->dfp.type & DP_DS_PORT_TYPE_VGA) {
+			intel_dp->dfp.dot_clk = dfp_info[1] * 8 * 1000;
+			DRM_DEBUG_KMS("max pixel rate for VGA is %d kHz\n", intel_dp->dfp.dot_clk);
+		}
+	}
+}
+
 enum irqreturn
 intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 {
@@ -4599,6 +4628,11 @@  intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 	power_domain = intel_display_port_aux_power_domain(intel_encoder);
 	intel_display_power_get(dev_priv, power_domain);
 
+	intel_dp->dfp.present = intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] & 0x1;
+
+	if (intel_dp->dfp.present)
+		intel_dp_get_dfp(intel_dp);
+
 	if (long_hpd) {
 		/* indicate that we need to restart link training */
 		intel_dp->train_set_valid = false;
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 21dee3f..9798a59 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -794,6 +794,13 @@  enum link_m_n_set {
 	M2_N2
 };
 
+struct intel_dp_dfp {
+	bool present;
+	int type;
+	bool detailed_cap_info;
+	int dot_clk; /* pixel rate for VGA dongles */
+};
+
 struct intel_dp {
 	i915_reg_t output_reg;
 	i915_reg_t aux_ch_ctl_reg;
@@ -861,6 +868,8 @@  struct intel_dp {
 
 	bool train_set_valid;
 
+	struct intel_dp_dfp dfp;
+
 	/* Displayport compliance testing */
 	unsigned long compliance_test_type;
 	unsigned long compliance_test_data;