[PATCH 2/2] nvme-apple: Prevent tag collision across queues even if tag space is shared

[Nick Chan]

Sven Peter 於 2026/6/7 凌晨12:12 寫道:
> On 06.06.26 15:25, Nick Chan wrote:
>> From: Yuriy Havrylyuk <yhavry at gmail.com>
>>
>> Apple NVMe controllers require tags of pending commands to not be shared
>> across admin and IO queues. However, on Apple A11 without linear SQ, it is
>> not possible for either queue to skip over some tags and must go from 0 to
>> the configured maximum before wrapping around.
>>
>> If a pending command tag is duplicated across queues, the firmware
>> crashes with: "duplicate tag error for tag N", with N being the tag.
>>
>> Instead of partitioning the tag space, which is not possible without
>> linear SQ, 
> 
> Isn't that just what the pci.c driver does with NVME_QUIRK_SHARED_TAGS 
> for the T2 macs or what we do in this driver with
> 	if (anv->hw->has_lsq_nvmmu)
> 		anv->tagset.reserved_tags = APPLE_NVME_AQ_DEPTH;
> ?

After adjusting the apple_nvme_submit_cmd_t8015() function to account for
the admin queue depth, it seems that the existing workaround for M1 of
reserving two tags for the admin queue works on A11 as well.

Will post a much simplified v2.

Best regards,
Nick Chan

> 
> 
> Sven
>