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From: Nick Owens <mischief@offblast.org>
To: 9front@9front.org
Subject: Re: [9front] bug: audiohda broken in qemu
Date: Tue, 27 Oct 2020 03:53:47 -0700	[thread overview]
Message-ID: <CAH_zEu74Q6NjzEqHB--zmQZUTMXHzmX2DyoQof6=vRixfNg7gg@mail.gmail.com> (raw)
In-Reply-To: <CAH_zEu4zEzQcjsyhnBkkr2=WeQTiWubVmHOD7xzxN6GkgNRM+w@mail.gmail.com>

following up on my previous idea, i enabled RIRB interrupts but clear
them in hdacmd, with RINTCNT set to 1. this seems to work.

http://okturing.com/src/9629/body

is there any way to improve this?

On Tue, Oct 27, 2020 at 3:23 AM Nick Owens <mischief@offblast.org> wrote:
>
>  On Tue, Oct 27, 2020 at 2:48 AM <cinap_lenrek@felloff.net> wrote:
> >
> > very odd, because we dont even use IRB interrupts at all.
> > in hdacmd(), you can see we just poll the irb write
> > pointer instead...
> >
> > note also that the irb ring has a variable size, it
> > can go from 2, 16 to 256 entries. so programming that
> > register with a out of range value might be a bad idea.
> >
> > i wonder why it fails with intcnt = 1, it seems the response
> > counter is never reset in qemu so just bumping the count
> > will just then make it fail after 0xC0 responses?
> >
> > maybe you can try running the vendor command in a loop
> > with your change and see if it starts failing once we
> > reach the count?
>
> yes, running Getparm in enumcodec() in a loop (0xC0+n times) leads to
> driver probing failure:
>
> intel-hda: read  CORBWP          : 0xbf (ffff)
> intel-hda: write CORBWP          : 0xc0 (ffff)
> intel-hda: intel_hda_corb_run: [rp 0xc0] verb 0x000f0000
> hda-duplex: hda_audio_command: nid 0 (root), verb 0xf00, payload 0x0
> intel-hda: intel_hda_response: [wp 0xc0] response 0x1af40022, extra
> 0x0
> intel-hda: intel_hda_response: rirb count reached (192)
> intel-hda: intel_hda_corb_run: corb ring empty
> intel-hda: read  RIRBWP          : 0xc0 (ffff)
> intel-hda: previous register op repeated 1 times
> intel-hda: read  CORBRP          : 0xc0 (ffff)
> intel-hda: read  CORBWP          : 0xc0 (ffff)
> intel-hda: write CORBWP          : 0xc1 (ffff)
> intel-hda: intel_hda_corb_run: rirb count reached
> intel-hda: read  RIRBWP          : 0xc0 (ffff)
> #A0: no audio codecs found
>
> >
> > the fix might be that we need to clear the response
> > interrupt status flag in rirbsts (bit 0) after or
> > before each command?
>
> FWICT qemu only resets the RIRB counter *if* you had RIRB interrupts
> on previously, and we arent using RIRB interrupts:
>
> https://git.qemu.org/?p=qemu.git;a=blob;f=hw/audio/intel-hda.c;h=4330213fff167071800216c49607c5f18022cc20;hb=HEAD#l555
>
> so what is the solution here? use RIRB interrupts?
>
> >
> > --
> > cinap


  reply	other threads:[~2020-10-27 10:54 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-27  4:39 Nick Owens
2020-10-27  8:16 ` Anthony Martin
2020-10-27  9:04   ` Anthony Martin
2020-10-27  9:30   ` [9front] " Nick Owens
2020-10-27  9:48 ` [9front] " cinap_lenrek
2020-10-27 10:23   ` Nick Owens
2020-10-27 10:53     ` Nick Owens [this message]
2020-10-27 20:00       ` Nick Owens

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