Re: [PATCH 1/2] ALSA: hda/hdmi: Add helper function to check if a device is HDMI codec

Takashi Iwai
2023-11-28T09:39:51Z

On Tue, 28 Nov 2023 10:10:48 +0100,
Péter Ujfalusi wrote:
>
>
>
> On 27/11/2023 17:43, Takashi Iwai wrote:
> > On Mon, 27 Nov 2023 16:40:57 +0100,
> >>> --- a/include/sound/hdaudio.h
> >>> +++ b/include/sound/hdaudio.h
> >>> @@ -95,6 +95,7 @@ struct hdac_device {
> >>> bool lazy_cache:1; /* don't wake up for writes */
> >>> bool caps_overwriting:1; /* caps overwrite being in process */
> >>> bool cache_coef:1; /* cache COEF read/write too */
> >>> + bool is_hdmi:1; /* a HDMI/DP codec */
> >>> unsigned int registered:1; /* codec was registered */
> >>> };
> >>>
> >>> --- a/sound/pci/hda/patch_hdmi.c
> >>> +++ b/sound/pci/hda/patch_hdmi.c
> >>> @@ -2597,6 +2597,7 @@ static int patch_generic_hdmi(struct hda_codec *codec)
> >>> }
> >>>
> >>> generic_hdmi_init_per_pins(codec);
> >>> + codec->core.is_hdmi = true;
> >>> return 0;
> >>> }
> >>>
> >>> @@ -3472,6 +3473,7 @@ static int patch_simple_hdmi(struct hda_codec *codec,
> >>> spec->pcm_playback = simple_pcm_playback;
> >>>
> >>> codec->patch_ops = simple_hdmi_patch_ops;
> >>> + codec->core.is_hdmi = true;
> >>>
> >>> return 0;
> >>> }
> >>
> >> I see, so this is what I was not sure how to do ;)
> >> I will rework the series and resend tomorrow.
> >>
> >> Thanks for the code snippet, I will make you as author of it, if it is
> >> OK for you.
> >
> > Sure, no problem.
>
> The flag does not work with SOF stack which uses the hdac_hda codec driver:
>
> patch_generic_hdmi() and patch_simple_hdmi() is not entered at all, so
> the flag is not set.
>
> The codec driver have is_hdmi_codec() helper to check the struct
> hda_pcm.pcm_type, but that is not set early enough either.
>
> The is HDMI or not needs to be known in hdac_hda_dev_probe(), I think
> this was one of the reason I have opted to have the exported function.
> We just don't have other information at the dev probe time.
>
> # dmesg | grep peter
> [ 3.810841] [peter] hdac_hda_dev_probe: is_hdmi_codec(): 0
> [ 3.810846] [peter] hdac_hda_dev_probe: hdev->is_hdmi: 0
> [ 3.810848] [peter] hdac_hda_dev_probe: snd_hda_device_is_hdmi(): 0
> ...
> [ 3.814497] [peter] hdac_hda_dev_probe: is_hdmi_codec(): 0
> [ 3.814499] [peter] hdac_hda_dev_probe: hdev->is_hdmi: 0
> [ 3.814500] [peter] hdac_hda_dev_probe: snd_hda_device_is_hdmi(): 1
> ...
> [ 3.986610] [peter] generic_hdmi_build_pcms: ENTER
> [ 3.986627] [peter] hdac_hda_codec_probe: is_hdmi_codec(): 1
> ...
> [ 3.996383] [peter] snd_hda_parse_pin_defcfg: ENTER
> [ 4.001562] [peter] hdac_hda_codec_probe: is_hdmi_codec(): 0

Hm... I still find it's a bad move to use an exported symbol from
another codec driver.

And, I wonder what if you have a system that has only one HDMI codec
without analog one? Would it still work with your change?

Takashi