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

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On Mon, 22 Jul 2019 17:35:09 +0200,
Alex Deucher wrote:
> 
> On Mon, Jul 22, 2019 at 11:21 AM Takashi Iwai <tiwai@xxxxxxx> 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.

> 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 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).


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@xxxxxxx>
> > > >>> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
> > > >>> ---
> > > >>>    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@xxxxxxxxxxxxxxxxxxxxx
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> 
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