[Intel-gfx] [PATCH] drm/i915/dp: Add dpcd link_rate quirk for Apple 15" MBP 2017 (v2)

[Intel-gfx] [PATCH] drm/i915/dp: Add dpcd link_rate quirk for Apple 15" MBP 2017 (v2)

[Mario Kleiner]

This fixes a problem found on the MacBookPro 2017 Retina panel.

The panel reports 10 bpc color depth in its EDID, and the
firmware chooses link settings at boot which support enough
bandwidth for 10 bpc (324000 kbit/sec = multiplier 0xc),
but the DP_MAX_LINK_RATE dpcd register only reports
2.7 Gbps (multiplier value 0xa) as possible, in direct
contradiction of what the firmware successfully set up.

This restricts the panel to 8 bpc, not providing the full
color depth of the panel.

This patch adds a quirk specific to the MBP 2017 15" Retina
panel to add the additiional 324000 kbps link rate during
edp setup.

Link to previous discussion of a different attempted fix
with Ville and Jani:

https://patchwork.kernel.org/patch/11325935/

v2: Follow Jani's proposal of defining quirk_rates[] instead
    of just appending 324000. This for better clarity.

Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Tested-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/drm_dp_helper.c         |  2 ++
 drivers/gpu/drm/i915/display/intel_dp.c | 11 +++++++++++
 include/drm/drm_dp_helper.h             |  7 +++++++
 3 files changed, 20 insertions(+)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 5a103e9b3c86..36a371c016cb 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -1179,6 +1179,8 @@ static const struct dpcd_quirk dpcd_quirk_list[] = {
 	{ OUI(0x00, 0x00, 0x00), DEVICE_ID('C', 'H', '7', '5', '1', '1'), false, BIT(DP_DPCD_QUIRK_NO_SINK_COUNT) },
 	/* Synaptics DP1.4 MST hubs can support DSC without virtual DPCD */
 	{ OUI(0x90, 0xCC, 0x24), DEVICE_ID_ANY, true, BIT(DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) },
+	/* Apple MacBookPro 2017 15 inch eDP Retina panel reports too low DP_MAX_LINK_RATE */
+	{ OUI(0x00, 0x10, 0xfa), DEVICE_ID(101, 68, 21, 101, 98, 97), false, BIT(DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS) },
 };
 
 #undef OUI
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 4074d83b1a5f..c0d2c70b04fb 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -169,6 +169,17 @@ static void intel_dp_set_sink_rates(struct intel_dp *intel_dp)
 	};
 	int i, max_rate;
 
+	if (drm_dp_has_quirk(&intel_dp->desc,
+			     DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS)) {
+		/* Needed, e.g., for Apple MBP 2017, 15 inch eDP Retina panel */
+		static const int quirk_rates[] = { 162000, 270000, 324000 };
+
+		memcpy(intel_dp->sink_rates, quirk_rates, sizeof(quirk_rates));
+		intel_dp->num_sink_rates = ARRAY_SIZE(quirk_rates);
+
+		return;
+	}
+
 	max_rate = drm_dp_bw_code_to_link_rate(intel_dp->dpcd[DP_MAX_LINK_RATE]);
 
 	for (i = 0; i < ARRAY_SIZE(dp_rates); i++) {
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 262faf9e5e94..4b86a1f2a559 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -1532,6 +1532,13 @@ enum drm_dp_quirk {
 	 * The DSC caps can be read from the physical aux instead.
 	 */
 	DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD,
+	/**
+	 * @DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS:
+	 *
+	 * The device supports a link rate of 3.24 Gbps (multiplier 0xc) despite
+	 * the DP_MAX_LINK_RATE register reporting a lower max multiplier.
+	 */
+	DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS,
 };
 
 /**
-- 
2.20.1

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Re: [Intel-gfx] [PATCH] drm/i915/dp: Add dpcd link_rate quirk for Apple 15" MBP 2017 (v2)

[Jani Nikula]

On Thu, 05 Mar 2020, Mario Kleiner <mario.kleiner.de@gmail.com> wrote:
> This fixes a problem found on the MacBookPro 2017 Retina panel.
>
> The panel reports 10 bpc color depth in its EDID, and the
> firmware chooses link settings at boot which support enough
> bandwidth for 10 bpc (324000 kbit/sec = multiplier 0xc),
> but the DP_MAX_LINK_RATE dpcd register only reports
> 2.7 Gbps (multiplier value 0xa) as possible, in direct
> contradiction of what the firmware successfully set up.
>
> This restricts the panel to 8 bpc, not providing the full
> color depth of the panel.
>
> This patch adds a quirk specific to the MBP 2017 15" Retina
> panel to add the additiional 324000 kbps link rate during
> edp setup.
>
> Link to previous discussion of a different attempted fix
> with Ville and Jani:
>
> https://patchwork.kernel.org/patch/11325935/
>
> v2: Follow Jani's proposal of defining quirk_rates[] instead
>     of just appending 324000. This for better clarity.
>
> Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
> Tested-by: Mario Kleiner <mario.kleiner.de@gmail.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Jani Nikula <jani.nikula@intel.com>

As much as I dislike quirks, I think we did exhaust other options when
we debugged this, and this is now very nicely isolated. Thanks for the
patch.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

I'll merge once the CI results are in, mostly to ensure this doesn't
impact other platforms, as we don't have the machine in the CI farm.

> ---
>  drivers/gpu/drm/drm_dp_helper.c         |  2 ++
>  drivers/gpu/drm/i915/display/intel_dp.c | 11 +++++++++++
>  include/drm/drm_dp_helper.h             |  7 +++++++
>  3 files changed, 20 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
> index 5a103e9b3c86..36a371c016cb 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -1179,6 +1179,8 @@ static const struct dpcd_quirk dpcd_quirk_list[] = {
>  	{ OUI(0x00, 0x00, 0x00), DEVICE_ID('C', 'H', '7', '5', '1', '1'), false, BIT(DP_DPCD_QUIRK_NO_SINK_COUNT) },
>  	/* Synaptics DP1.4 MST hubs can support DSC without virtual DPCD */
>  	{ OUI(0x90, 0xCC, 0x24), DEVICE_ID_ANY, true, BIT(DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) },
> +	/* Apple MacBookPro 2017 15 inch eDP Retina panel reports too low DP_MAX_LINK_RATE */
> +	{ OUI(0x00, 0x10, 0xfa), DEVICE_ID(101, 68, 21, 101, 98, 97), false, BIT(DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS) },
>  };
>  
>  #undef OUI
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 4074d83b1a5f..c0d2c70b04fb 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -169,6 +169,17 @@ static void intel_dp_set_sink_rates(struct intel_dp *intel_dp)
>  	};
>  	int i, max_rate;
>  
> +	if (drm_dp_has_quirk(&intel_dp->desc,
> +			     DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS)) {
> +		/* Needed, e.g., for Apple MBP 2017, 15 inch eDP Retina panel */
> +		static const int quirk_rates[] = { 162000, 270000, 324000 };
> +
> +		memcpy(intel_dp->sink_rates, quirk_rates, sizeof(quirk_rates));
> +		intel_dp->num_sink_rates = ARRAY_SIZE(quirk_rates);
> +
> +		return;
> +	}
> +
>  	max_rate = drm_dp_bw_code_to_link_rate(intel_dp->dpcd[DP_MAX_LINK_RATE]);
>  
>  	for (i = 0; i < ARRAY_SIZE(dp_rates); i++) {
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 262faf9e5e94..4b86a1f2a559 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -1532,6 +1532,13 @@ enum drm_dp_quirk {
>  	 * The DSC caps can be read from the physical aux instead.
>  	 */
>  	DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD,
> +	/**
> +	 * @DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS:
> +	 *
> +	 * The device supports a link rate of 3.24 Gbps (multiplier 0xc) despite
> +	 * the DP_MAX_LINK_RATE register reporting a lower max multiplier.
> +	 */
> +	DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS,
>  };
>  
>  /**

-- 
Jani Nikula, Intel Open Source Graphics Center
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Re: [Intel-gfx] [PATCH] drm/i915/dp: Add dpcd link_rate quirk for Apple 15" MBP 2017 (v2)

[Jani Nikula]

On Thu, 05 Mar 2020, Jani Nikula <jani.nikula@intel.com> wrote:
> On Thu, 05 Mar 2020, Mario Kleiner <mario.kleiner.de@gmail.com> wrote:
>> This fixes a problem found on the MacBookPro 2017 Retina panel.
>>
>> The panel reports 10 bpc color depth in its EDID, and the
>> firmware chooses link settings at boot which support enough
>> bandwidth for 10 bpc (324000 kbit/sec = multiplier 0xc),
>> but the DP_MAX_LINK_RATE dpcd register only reports
>> 2.7 Gbps (multiplier value 0xa) as possible, in direct
>> contradiction of what the firmware successfully set up.
>>
>> This restricts the panel to 8 bpc, not providing the full
>> color depth of the panel.
>>
>> This patch adds a quirk specific to the MBP 2017 15" Retina
>> panel to add the additiional 324000 kbps link rate during
>> edp setup.
>>
>> Link to previous discussion of a different attempted fix
>> with Ville and Jani:
>>
>> https://patchwork.kernel.org/patch/11325935/
>>
>> v2: Follow Jani's proposal of defining quirk_rates[] instead
>>     of just appending 324000. This for better clarity.
>>
>> Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
>> Tested-by: Mario Kleiner <mario.kleiner.de@gmail.com>
>> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
>> Cc: Jani Nikula <jani.nikula@intel.com>
>
> As much as I dislike quirks, I think we did exhaust other options when
> we debugged this, and this is now very nicely isolated. Thanks for the
> patch.
>
> Reviewed-by: Jani Nikula <jani.nikula@intel.com>
>
> I'll merge once the CI results are in, mostly to ensure this doesn't
> impact other platforms, as we don't have the machine in the CI farm.

Note to self, add this when merging per Mario's suggestion:

Cc: stable@vger.kernel.org

>
>> ---
>>  drivers/gpu/drm/drm_dp_helper.c         |  2 ++
>>  drivers/gpu/drm/i915/display/intel_dp.c | 11 +++++++++++
>>  include/drm/drm_dp_helper.h             |  7 +++++++
>>  3 files changed, 20 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
>> index 5a103e9b3c86..36a371c016cb 100644
>> --- a/drivers/gpu/drm/drm_dp_helper.c
>> +++ b/drivers/gpu/drm/drm_dp_helper.c
>> @@ -1179,6 +1179,8 @@ static const struct dpcd_quirk dpcd_quirk_list[] = {
>>  	{ OUI(0x00, 0x00, 0x00), DEVICE_ID('C', 'H', '7', '5', '1', '1'), false, BIT(DP_DPCD_QUIRK_NO_SINK_COUNT) },
>>  	/* Synaptics DP1.4 MST hubs can support DSC without virtual DPCD */
>>  	{ OUI(0x90, 0xCC, 0x24), DEVICE_ID_ANY, true, BIT(DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) },
>> +	/* Apple MacBookPro 2017 15 inch eDP Retina panel reports too low DP_MAX_LINK_RATE */
>> +	{ OUI(0x00, 0x10, 0xfa), DEVICE_ID(101, 68, 21, 101, 98, 97), false, BIT(DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS) },
>>  };
>>  
>>  #undef OUI
>> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
>> index 4074d83b1a5f..c0d2c70b04fb 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>> @@ -169,6 +169,17 @@ static void intel_dp_set_sink_rates(struct intel_dp *intel_dp)
>>  	};
>>  	int i, max_rate;
>>  
>> +	if (drm_dp_has_quirk(&intel_dp->desc,
>> +			     DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS)) {
>> +		/* Needed, e.g., for Apple MBP 2017, 15 inch eDP Retina panel */
>> +		static const int quirk_rates[] = { 162000, 270000, 324000 };
>> +
>> +		memcpy(intel_dp->sink_rates, quirk_rates, sizeof(quirk_rates));
>> +		intel_dp->num_sink_rates = ARRAY_SIZE(quirk_rates);
>> +
>> +		return;
>> +	}
>> +
>>  	max_rate = drm_dp_bw_code_to_link_rate(intel_dp->dpcd[DP_MAX_LINK_RATE]);
>>  
>>  	for (i = 0; i < ARRAY_SIZE(dp_rates); i++) {
>> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
>> index 262faf9e5e94..4b86a1f2a559 100644
>> --- a/include/drm/drm_dp_helper.h
>> +++ b/include/drm/drm_dp_helper.h
>> @@ -1532,6 +1532,13 @@ enum drm_dp_quirk {
>>  	 * The DSC caps can be read from the physical aux instead.
>>  	 */
>>  	DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD,
>> +	/**
>> +	 * @DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS:
>> +	 *
>> +	 * The device supports a link rate of 3.24 Gbps (multiplier 0xc) despite
>> +	 * the DP_MAX_LINK_RATE register reporting a lower max multiplier.
>> +	 */
>> +	DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS,
>>  };
>>  
>>  /**

-- 
Jani Nikula, Intel Open Source Graphics Center
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[Intel-gfx] ✗ Fi.CI.BUILD: failure for drm/i915/dp: Add dpcd link_rate quirk for Apple 15" MBP 2017 (rev2)

[Patchwork]

== Series Details ==

Series: drm/i915/dp: Add dpcd link_rate quirk for Apple 15" MBP 2017 (rev2)
URL   : https://patchwork.freedesktop.org/series/74100/
State : failure

== Summary ==

Applying: drm/i915/dp: Add dpcd link_rate quirk for Apple 15" MBP 2017 (v2)
Using index info to reconstruct a base tree...
M	drivers/gpu/drm/drm_dp_helper.c
M	drivers/gpu/drm/i915/display/intel_dp.c
M	include/drm/drm_dp_helper.h
Falling back to patching base and 3-way merge...
Auto-merging include/drm/drm_dp_helper.h
CONFLICT (content): Merge conflict in include/drm/drm_dp_helper.h
Auto-merging drivers/gpu/drm/i915/display/intel_dp.c
Auto-merging drivers/gpu/drm/drm_dp_helper.c
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch' to see the failed patch
Patch failed at 0001 drm/i915/dp: Add dpcd link_rate quirk for Apple 15" MBP 2017 (v2)
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

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Re: [Intel-gfx] ✗ Fi.CI.BUILD: failure for drm/i915/dp: Add dpcd link_rate quirk for Apple 15" MBP 2017 (rev2)

[Jani Nikula]

On Thu, 05 Mar 2020, Patchwork <patchwork@emeril.freedesktop.org> wrote:
> == Series Details ==
>
> Series: drm/i915/dp: Add dpcd link_rate quirk for Apple 15" MBP 2017 (rev2)
> URL   : https://patchwork.freedesktop.org/series/74100/
> State : failure
>
> == Summary ==
>
> Applying: drm/i915/dp: Add dpcd link_rate quirk for Apple 15" MBP 2017 (v2)
> Using index info to reconstruct a base tree...
> M	drivers/gpu/drm/drm_dp_helper.c
> M	drivers/gpu/drm/i915/display/intel_dp.c
> M	include/drm/drm_dp_helper.h
> Falling back to patching base and 3-way merge...
> Auto-merging include/drm/drm_dp_helper.h
> CONFLICT (content): Merge conflict in include/drm/drm_dp_helper.h
> Auto-merging drivers/gpu/drm/i915/display/intel_dp.c
> Auto-merging drivers/gpu/drm/drm_dp_helper.c
> error: Failed to merge in the changes.
> hint: Use 'git am --show-current-patch' to see the failed patch
> Patch failed at 0001 drm/i915/dp: Add dpcd link_rate quirk for Apple 15" MBP 2017 (v2)
> When you have resolved this problem, run "git am --continue".
> If you prefer to skip this patch, run "git am --skip" instead.
> To restore the original branch and stop patching, run "git am --abort".

I missed that this fails to apply, please rebase on top of current
drm-tip and repost.

Thanks,
Jani.


>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Jani Nikula, Intel Open Source Graphics Center
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