Re: [PATCH] ASoC: soc-dai: don't use dev_{set/get}_drvdata() on DAI

[Charles Keepax <ckeepax@opensource.cirrus.com>]

On Thu, Mar 05, 2026 at 01:14:30PM +0000, Charles Keepax wrote:
> On Thu, Mar 05, 2026 at 01:56:44AM +0000, Kuninori Morimoto wrote:
> > We can re-use this dai->priv for snd_soc_dai_set_drvdata() (B) instead,
> > and avoid the issue.
> 
> Hm... the patch looks pretty reasonable to me but does seem to
> cause issues on my system. I will try to find some time to
> investigate further:
> 
> Mar 05 13:06:17.645064 ck-upx-mtl kernel: i915 0000:00:02.0: [drm] *ERROR* DC state mismatch (0x0 -> 0x2)
> Mar 05 13:06:17.647247 ck-upx-mtl kernel: BUG: kernel NULL pointer dereference, address: 0000000000000000
> Mar 05 13:06:17.647257 ck-upx-mtl kernel: #PF: supervisor read access in kernel mode
> Mar 05 13:06:17.647265 ck-upx-mtl kernel: #PF: error_code(0x0000) - not-present page
> Mar 05 13:06:17.647270 ck-upx-mtl kernel: PGD 0 P4D 0 
> Mar 05 13:06:17.647276 ck-upx-mtl kernel: Oops: Oops: 0000 [#1] SMP NOPTI
> Mar 05 13:06:17.647281 ck-upx-mtl kernel: CPU: 0 UID: 0 PID: 98 Comm: (udev-worker) Tainted: G            E 7.0.0-rc2-mykernel #1 PREEMPT(lazy) Mar 05 13:06:17.647286 ck-upx-mtl kernel: Tainted: [E]=UNSIGNED_MODULE
> Mar 05 13:06:17.647291 ck-upx-mtl kernel: Hardware name: AAEON UPX-MTL01/UPX-MTL01, BIOS UXMTAM13 02/13/2025
> Mar 05 13:06:17.647295 ck-upx-mtl kernel: RIP: 0010:intel_dmc_update_dc6_allowed_count+0x17/0xb0 [i915]
> 
> I wonder if maybe something is mixing these functions and
> expecting them to set the same thing?

Ah ok yeah looking a little further it seems an awful lot of
machine drivers use snd_soc_dai_get_drvdata but very few use
snd_soc_dai_set_drvdata, so I think a large amount of the world
is relying on these two functions accessing the same stuff.

Thanks,
Charles