Re: [PATCH 1/2] drm/radeon: Add HD-audio component notifier support

[Alex Deucher <alexdeucher@gmail.com>]

On Mon, Jul 22, 2019 at 11:47 AM Takashi Iwai <tiwai@suse.de> wrote:
>
> On Mon, 22 Jul 2019 17:35:09 +0200,
> Alex Deucher wrote:
> >
> > On Mon, Jul 22, 2019 at 11:21 AM Takashi Iwai <tiwai@suse.de> wrote:
> > >
> > > On Mon, 22 Jul 2019 17:07:09 +0200,
> > > Koenig, Christian wrote:
> > > >
> > > > Am 22.07.19 um 16:53 schrieb Takashi Iwai:
> > > > > On Mon, 22 Jul 2019 16:44:06 +0200,
> > > > > Koenig, Christian wrote:
> > > > >> Am 22.07.19 um 16:38 schrieb Takashi Iwai:
> > > > >>> This patch adds the support for the notification of HD-audio hotplug
> > > > >>> via the already existing drm_audio_component framework to radeon
> > > > >>> driver.  This allows us more reliable hotplug notification and ELD
> > > > >>> transfer without accessing HD-audio bus; it's more efficient, and more
> > > > >>> importantly, it works without waking up the runtime PM.
> > > > >>>
> > > > >>> The implementation is rather simplistic: radeon driver provides the
> > > > >>> get_eld ops for HD-audio, and it notifies the audio hotplug via
> > > > >>> pin_eld_notify callback upon each radeon_audio_enable() call.
> > > > >>> The pin->id is referred as the port number passed to the notifier
> > > > >>> callback, and the corresponding connector is looked through the
> > > > >>> encoder list in the get_eld callback in turn.
> > > > >> On most older Radeon parts you only got one audio codec which can be
> > > > >> routed to multiple connectors.
> > > > >>
> > > > >> As far as I can see this is not correctly supported with this framework
> > > > >> here since we only grab the first ELD. Is that correct?
> > > > > Hrm, how does it work currently (without the patch) in the hardware
> > > > > level?  I mean, the unsolicited event is still triggered via HD-audio
> > > > > bus as well as the partial ELD pass-through via HD-audio.  Isn't the
> > > > > reported pin ID corresponding to that connector?
> > > >
> > > > The hardware we are talking about here doesn't have ELD support at all.
> > > >
> > > > So no ELD pass-through or unsolicited event when something is connected.
> > > >
> > > > You basically have to setup the capabilities in the applications manually.
> > >
> > > Well, if ELD isn't passed, the HDMI audio doesn't work at all -- even
> > > for the driver as of today.  So we're talking about a stuff that is
> > > already broken now, if any.
> > >
> > > > >> Additional to that I'm not sure if that is the right design for AMD
> > > > >> hardware in general since we don't really support ELD in the first place.
> > > > > ELD is a kind of mandatory and we've assembled the ELD from the
> > > > > partial information taken via HD-audio bus like speaker allocation and
> > > > > other bits, so far.  I thought the very same information is found in
> > > > > connector->edid that is always parsed at EDID parsing time.
> > > > >
> > > > > Let me know if I'm obviously overlooking something.
> > > >
> > > > The hardware we are talking about existed way before the ELD standard.
> > > > So nothing from the ELD standard is supported here.
> > > >
> > > > I mean it would be great to get this cleaned up, but you need to take
> > > > care all those nasty corner cases not supported by ELD.
> > >
> > > That's not clear to me: the ELD information bits are filled in
> > > drm_edid_to_eld() generically for the given EDID.  Do you mean that
> > > this isn't applied to the old radeon chip?  IOW, doesn't such a chip
> > > read EDID at all...?
> >
> > No AMD audio hw uses ELD.  The original hw design for display auto
> > pre-dated ELD.  the display driver updates the the hw state and that
> > state is updated in the audio hw as well.  So there is an internal hw
> > interface between the two drivers.  The display driver updates via GPU
> > MMIO, and the audio driver can interact with that state via AMD
> > specific VERBs.  See this document:
> > http://developer.amd.com/wordpress/media/2013/10/AMD_HDA_verbs_v2.pdf
>
> Yes, that's what I mentioned as "assembling ELD in HD-audio side".
> The HD-audio driver has an AMD-specific code for building up the ELD
> from these partial bits.
>
> But my question is whether these AMD chips do read EDID and process
> via the standard EDID helper (drm_add_edid_modes(), etc).  If yes, the
> ELD is filled up there, and we can use the same information from there
> as done in my patch.
>

Yes, we do use the standard helpers for fetching EDID and parsing the
audio related extensions.  IIRC, we used to call the drm ELD helpers
directly to populate everything even before they moved into the core
drm EDID helpers.

> > On older AMD chips (everything prior to SI chips IIRC), had a single
> > audio engine which could be routed to one or more display connectors.
>
> And does really appear as multiple HD-audio pins?  Unless that
> happens, the picking up one connector should work.

I don't remember exactly how it's exposed on the audio side.  I think
it's a single pin.

>
>
> > > I know that the old radeon chip doesn't pass the ELD information via
> > > HD-audio bus unlike others.  For such chips, we've assembled the ELD
> > > from the partial information, as I already mentioned.
> > >
> > > > Like one audio codec routed to multiple physical connectors. In theory
> > > > you even have the ability to route the left and right channel to
> > > > different connectors.
> > >
> > > That's a question how currently it's exposed in the hardware level at
> > > all to HD-audio side.  Again, my patchset tries to simplify this
> > > communication -- between gfx and HD-audio codec chip.  If the
> > > translation of connector / pin can't be done in the way I implemented,
> > > I'd like to hear how the hardware actually decides the HD-audio pin
> > > index from the given configuration.
> >
> > On AMD hw the ELD is technically not required.  If everything has
> > power, the internal interface works as expected.  The only case where
> > we have a problem is runtime pm on HG platforms where I think we end
> > up missing updates due to timing of powering up the relevant hw.
>
> To clarify: the ELD meant in my comments is the ELD information
> exposed from HD-audio driver.  This is mandatory for making the audio
> working, so far, and currently HD-audio driver even disables if ELD
> isn't available.  Again, for AMD, the ELD is assembled from other
> information sources.
>
> I hope that, with my patch, that complex path can be avoided as well
> by passing the already existing data (already parsed from EDID).
>

RIght, I agree.  I think it makes it more robust by handling the
corner cases that don't work with the hw only design.

Alex

>
> thanks,
>
> Takashi
>
> >
> > Alex
> >
> > >
> > > > I think nouveau has an even nastier case where you have an audio codec
> > > > which can be attached both to a normal audio plug as well as to a
> > > > display device to route stuff over HDMI.
> > >
> > > The nouveau looks even more straightforward :)
> > >
> > > > You won't find any of that on modern hardware, so I'm not sure if it's
> > > > worth putting to much effort into it :)
> > >
> > > Heh, I'm fine to drop the radeon part, as it's becoming dead
> > > nowadays, if you think it being too risky.  For AMDGPU, you guys seem
> > > working on it, and I'd just wait for the final patches.
> > >
> > > The nouveau is still in active deployment and development, so I'd like
> > > to have it done there, though.
> > >
> > >
> > > thanks,
> > >
> > > Takashi
> > >
> > > >
> > > > Regards,
> > > > Christian.
> > > >
> > > > >
> > > > >
> > > > > Thanks!
> > > > >
> > > > > Takashi
> > > > >
> > > > >
> > > > >> Regards,
> > > > >> Christian.
> > > > >>
> > > > >>> The bind and unbind callbacks handle the device-link so that it
> > > > >>> assures the PM call order.
> > > > >>>
> > > > >>> Acked-by: Jim Qu <Jim.Qu@amd.com>
> > > > >>> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> > > > >>> ---
> > > > >>>    drivers/gpu/drm/Kconfig               |  1 +
> > > > >>>    drivers/gpu/drm/radeon/radeon.h       |  3 ++
> > > > >>>    drivers/gpu/drm/radeon/radeon_audio.c | 92 +++++++++++++++++++++++++++++++++++
> > > > >>>    3 files changed, 96 insertions(+)
> > > > >>>
> > > > >>> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> > > > >>> index 1d80222587ad..8b44cc458830 100644
> > > > >>> --- a/drivers/gpu/drm/Kconfig
> > > > >>> +++ b/drivers/gpu/drm/Kconfig
> > > > >>> @@ -209,6 +209,7 @@ config DRM_RADEON
> > > > >>>           select HWMON
> > > > >>>           select BACKLIGHT_CLASS_DEVICE
> > > > >>>           select INTERVAL_TREE
> > > > >>> + select SND_HDA_COMPONENT if SND_HDA_CORE
> > > > >>>           help
> > > > >>>             Choose this option if you have an ATI Radeon graphics card.  There
> > > > >>>             are both PCI and AGP versions.  You don't need to choose this to
> > > > >>> diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
> > > > >>> index 32808e50be12..2973284b7961 100644
> > > > >>> --- a/drivers/gpu/drm/radeon/radeon.h
> > > > >>> +++ b/drivers/gpu/drm/radeon/radeon.h
> > > > >>> @@ -75,6 +75,7 @@
> > > > >>>    #include <drm/ttm/ttm_execbuf_util.h>
> > > > >>>
> > > > >>>    #include <drm/drm_gem.h>
> > > > >>> +#include <drm/drm_audio_component.h>
> > > > >>>
> > > > >>>    #include "radeon_family.h"
> > > > >>>    #include "radeon_mode.h"
> > > > >>> @@ -1761,6 +1762,8 @@ struct r600_audio {
> > > > >>>           struct radeon_audio_funcs *hdmi_funcs;
> > > > >>>           struct radeon_audio_funcs *dp_funcs;
> > > > >>>           struct radeon_audio_basic_funcs *funcs;
> > > > >>> + struct drm_audio_component *component;
> > > > >>> + bool component_registered;
> > > > >>>    };
> > > > >>>
> > > > >>>    /*
> > > > >>> diff --git a/drivers/gpu/drm/radeon/radeon_audio.c b/drivers/gpu/drm/radeon/radeon_audio.c
> > > > >>> index b9aea5776d3d..976502e31c43 100644
> > > > >>> --- a/drivers/gpu/drm/radeon/radeon_audio.c
> > > > >>> +++ b/drivers/gpu/drm/radeon/radeon_audio.c
> > > > >>> @@ -23,6 +23,7 @@
> > > > >>>     */
> > > > >>>
> > > > >>>    #include <linux/gcd.h>
> > > > >>> +#include <linux/component.h>
> > > > >>>
> > > > >>>    #include <drm/drm_crtc.h>
> > > > >>>    #include "radeon.h"
> > > > >>> @@ -242,6 +243,14 @@ static struct radeon_audio_funcs dce6_dp_funcs = {
> > > > >>>           .dpms = evergreen_dp_enable,
> > > > >>>    };
> > > > >>>
> > > > >>> +static void radeon_audio_component_notify(struct drm_audio_component *acomp,
> > > > >>> +                                   int port)
> > > > >>> +{
> > > > >>> + if (acomp && acomp->audio_ops && acomp->audio_ops->pin_eld_notify)
> > > > >>> +         acomp->audio_ops->pin_eld_notify(acomp->audio_ops->audio_ptr,
> > > > >>> +                                          port, -1);
> > > > >>> +}
> > > > >>> +
> > > > >>>    static void radeon_audio_enable(struct radeon_device *rdev,
> > > > >>>                                   struct r600_audio_pin *pin, u8 enable_mask)
> > > > >>>    {
> > > > >>> @@ -269,6 +278,8 @@ static void radeon_audio_enable(struct radeon_device *rdev,
> > > > >>>
> > > > >>>           if (rdev->audio.funcs->enable)
> > > > >>>                   rdev->audio.funcs->enable(rdev, pin, enable_mask);
> > > > >>> +
> > > > >>> + radeon_audio_component_notify(rdev->audio.component, pin->id);
> > > > >>>    }
> > > > >>>
> > > > >>>    static void radeon_audio_interface_init(struct radeon_device *rdev)
> > > > >>> @@ -292,6 +303,79 @@ static void radeon_audio_interface_init(struct radeon_device *rdev)
> > > > >>>           }
> > > > >>>    }
> > > > >>>
> > > > >>> +static int radeon_audio_component_get_eld(struct device *kdev, int port,
> > > > >>> +                                   int pipe, bool *enabled,
> > > > >>> +                                   unsigned char *buf, int max_bytes)
> > > > >>> +{
> > > > >>> + struct drm_device *dev = dev_get_drvdata(kdev);
> > > > >>> + struct drm_encoder *encoder;
> > > > >>> + struct radeon_encoder *radeon_encoder;
> > > > >>> + struct radeon_encoder_atom_dig *dig;
> > > > >>> + struct drm_connector *connector;
> > > > >>> + int ret = 0;
> > > > >>> +
> > > > >>> + *enabled = false;
> > > > >>> + list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
> > > > >>> +         if (!radeon_encoder_is_digital(encoder))
> > > > >>> +                 continue;
> > > > >>> +         radeon_encoder = to_radeon_encoder(encoder);
> > > > >>> +         dig = radeon_encoder->enc_priv;
> > > > >>> +         if (!dig->pin || dig->pin->id != port)
> > > > >>> +                 continue;
> > > > >>> +         connector = radeon_get_connector_for_encoder(encoder);
> > > > >>> +         if (connector) {
> > > > >>> +                 *enabled = true;
> > > > >>> +                 ret = drm_eld_size(connector->eld);
> > > > >>> +                 memcpy(buf, connector->eld, min(max_bytes, ret));
> > > > >>> +                 break;
> > > > >>> +         }
> > > > >>> + }
> > > > >>> +
> > > > >>> + return ret;
> > > > >>> +}
> > > > >>> +
> > > > >>> +static const struct drm_audio_component_ops radeon_audio_component_ops = {
> > > > >>> + .get_eld = radeon_audio_component_get_eld,
> > > > >>> +};
> > > > >>> +
> > > > >>> +static int radeon_audio_component_bind(struct device *kdev,
> > > > >>> +                                struct device *hda_kdev, void *data)
> > > > >>> +{
> > > > >>> + struct drm_device *dev = dev_get_drvdata(kdev);
> > > > >>> + struct radeon_device *rdev = dev->dev_private;
> > > > >>> + struct drm_audio_component *acomp = data;
> > > > >>> +
> > > > >>> + if (WARN_ON(!device_link_add(hda_kdev, kdev, DL_FLAG_STATELESS)))
> > > > >>> +         return -ENOMEM;
> > > > >>> +
> > > > >>> + drm_modeset_lock_all(dev);
> > > > >>> + acomp->ops = &radeon_audio_component_ops;
> > > > >>> + acomp->dev = kdev;
> > > > >>> + rdev->audio.component = acomp;
> > > > >>> + drm_modeset_unlock_all(dev);
> > > > >>> +
> > > > >>> + return 0;
> > > > >>> +}
> > > > >>> +
> > > > >>> +static void radeon_audio_component_unbind(struct device *kdev,
> > > > >>> +                                   struct device *hda_kdev, void *data)
> > > > >>> +{
> > > > >>> + struct drm_device *dev = dev_get_drvdata(kdev);
> > > > >>> + struct radeon_device *rdev = dev->dev_private;
> > > > >>> + struct drm_audio_component *acomp = data;
> > > > >>> +
> > > > >>> + drm_modeset_lock_all(dev);
> > > > >>> + rdev->audio.component = NULL;
> > > > >>> + acomp->ops = NULL;
> > > > >>> + acomp->dev = NULL;
> > > > >>> + drm_modeset_unlock_all(dev);
> > > > >>> +}
> > > > >>> +
> > > > >>> +static const struct component_ops radeon_audio_component_bind_ops = {
> > > > >>> + .bind   = radeon_audio_component_bind,
> > > > >>> + .unbind = radeon_audio_component_unbind,
> > > > >>> +};
> > > > >>> +
> > > > >>>    static int radeon_audio_chipset_supported(struct radeon_device *rdev)
> > > > >>>    {
> > > > >>>           return ASIC_IS_DCE2(rdev) && !ASIC_IS_NODCE(rdev);
> > > > >>> @@ -338,6 +422,9 @@ int radeon_audio_init(struct radeon_device *rdev)
> > > > >>>           for (i = 0; i < rdev->audio.num_pins; i++)
> > > > >>>                   radeon_audio_enable(rdev, &rdev->audio.pin[i], 0);
> > > > >>>
> > > > >>> + if (!component_add(rdev->dev, &radeon_audio_component_bind_ops))
> > > > >>> +         rdev->audio.component_registered = true;
> > > > >>> +
> > > > >>>           return 0;
> > > > >>>    }
> > > > >>>
> > > > >>> @@ -490,6 +577,11 @@ void radeon_audio_fini(struct radeon_device *rdev)
> > > > >>>                   radeon_audio_enable(rdev, &rdev->audio.pin[i], 0);
> > > > >>>
> > > > >>>           rdev->audio.enabled = false;
> > > > >>> +
> > > > >>> + if (rdev->audio.component_registered) {
> > > > >>> +         component_del(rdev->dev, &radeon_audio_component_bind_ops);
> > > > >>> +         rdev->audio.component_registered = false;
> > > > >>> + }
> > > > >>>    }
> > > > >>>
> > > > >>>    static void radeon_audio_set_dto(struct drm_encoder *encoder, unsigned int clock)
> > > >
> > > _______________________________________________
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> > > dri-devel@lists.freedesktop.org
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> >
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