Re: [PATCH] ALSA: hda: Enable sync-write operation as default for all controllers

[Jon Hunter <jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

On 14/07/2020 09:08, Jon Hunter wrote:
> Hi Takashi,
> 
> On 18/06/2020 15:40, Takashi Iwai wrote:
>> In the end we already enabled the sync-write mode for most of HD-audio
>> controllers including Intel, and it's no big merit to keep the async
>> write mode for the rest.  Let's make it as default and drop the
>> superfluous AZX_DCAPS_SYNC_WRITE bit flag.
>>
>> Also, avoid to set the allow_bus_reset flag, which is a quite unstable
>> and hackish behavior that was needed only for some early platforms
>> (decades ago).  The straight fallback to the single cmd mode is more
>> robust.
>>
>> Signed-off-by: Takashi Iwai <tiwai-l3A5Bk7waGM@public.gmane.org>
> 
> 
> I have noticed a regression in HDA playback on our Tegra186 Jetson TX2
> platform. Bisect is pointing to this patch and reverting this does
> appear to fix it. Interestingly, I am not seeing any problems on other
> Tegra platforms, however, Tegra186 does have the IOMMU enabled for HDA
> which is one different between the other platforms.
> 
> We can take a closer look at this for Tegra, but I am wondering if we
> revert this for Tegra for now.

By revert, I don't mean revert the entire change, but just disable the
sync-write for Tegra for now.

Jon

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