Re: ata timeout exceptions

[Damien Le Moal <dlemoal@kernel.org>]

On 12/20/25 13:03, Eyal Lebedinsky wrote:
> On 17/12/25 23:02, Niklas Cassel wrote:
>> On 17 December 2025 20:56:07 GMT+09:00, Eyal Lebedinsky <eyal@eyal.emu.id.au> wrote:
> 
> [trimmed]
> 
>>> Do you want me to try different max_sectors_kb values to see where it breaks?
>>>
>>
>> You can also try this:
>>
>> https://github.com/floatious/max-sectors-quirk
>>
>> It tries these max_sector_kb values:
>> declare -a sizes=(128 1024 2048 3072 4095 4096)
>>
>> You can simply modify the script if you want to try more intermediate sizes.
> 
> After testing the script on a sacrificial disk, I got brave and ran it on the offending disk.
> See comments after the test report.

From your test results, it seems that the drive actually correctly handles very
large write commands, but because it is a drive-managed SMR disk, such commands
can take a very long time to process (due to the drive needing internal garbage
collection first), which triggers a timeout and a reset as the ata subsystem
assumes that the drive has stopped responding.

Limiting write commands to smaller sizes seems to mostly avoid this issue, even
though I do not think that gives any guarantees that the same issue will not
happen for small writes too.

So my suggestion is that you run with something like "libata.force=[<port
ID>:]max_sec=1024" for that drive. We can also add a permanent quirk for it too,
but that would be a really more of a big hammer solution.

-- 
Damien Le Moal
Western Digital Research