Re: [PATCH] ata: libata-sata: retry hardreset when device detected but PHY not established

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

On 4/29/26 10:14, yangxingui wrote:
> 
> 
> On 2026/4/27 12:45, Damien Le Moal wrote:
>> On 4/27/26 10:51 AM, yangxingui wrote:
>>>
>>>
>>> On 2026/4/26 6:53, Damien Le Moal wrote:
>>>> On 4/25/26 15:04, Xingui Yang wrote:
>>>>> When sata_link_hardreset() detects that the link is offline, it currently
>>>>> returns immediately without distinguishing the reason. According to SATA
>>>>> specification, the SStatus register's det filed (bits 0-3) indicates:
>>>>>     - 0x0: No device detected, PHY not communicating
>>>>>     - 0x1: Device detected but PHY communication not established
>>>>>     - 0x3: Device detected and PHY communication established
>>>>>
>>>>> This patch helps improve device detection reliability and adds a check
>>>>> when the link is offline but det filed shows 0x1, return -EAGAIN to
>>>>> trigger retry, rather than giving up immediately.
>>>>>
>>>>> Signed-off-by: Xingui Yang <yangxingui@huawei.com>
>>>>
>>>> This is a pure ATA patch so please CC the linux-ide list, not the linux-scsi
>>>> list.
>>>
>>> Ok.
>>>>
>>>> Also, please check your mail setup: your email was in my Junk folder.
>>>
>>> Well, patche was sent using the git send command.
>>
>> Not git send-email, your smtp server. It probably has something wrong with
>> DMARC. All your emails endup in my junk folder.
> 
> Alright, it might be related to the company's SMTP server, but this 
> configuration is fixed, and I'm not quite sure how to fix it yet.
> 
>>
>>>> This is preceeded by a call to sata_link_resume(), which calls
>>>> sata_link_debounce() and that function makes sure that DET is stable. So if
>>>> after that DET still shows that their is no PHY, there is likely a big problem
>>>> with it and it is super slow to be established.
>>>>
>>>> In this case, I do not think that doing another hardreset is the right thing to
>>>> do. Have you tried increasing the deadline for hardreset ? That deadline is used
>>>> as the limit for the link debounce too.
>>>>
>>>> Do you have a specific controller/device where you see this issue ? What exactly
>>>> is the hardware setup where you see this issue ?
>>>
>>> Our customer imports and verifies a new disk, there is an occasional failure in
>>> performing a hard reset on the disk and no exception log is generated for
>>> resume and debounce.
>>
>> Does this hold for all disks or for only one or some models ?
> 
> It may be some models, It is not found on other disks.

Some model ? Which one ?

And please remove linux-scsi from your emails for this topic.

-- 
Damien Le Moal
Western Digital Research