Re: [PATCH] ata: libata-transport: fix {dma|pio|xfer}_mode sysfs files

[Sergei Shtylyov <sergei.shtylyov@gmail.com>]

On 6/7/22 3:37 AM, Damien Le Moal wrote:

[...]
>>>> The {dma|pio|xfer}_mode sysfs files are incorrectly handled by the
>>>> ata_bitfield_name_match() macro which leads to reading such kind of
>>>> nonsense from them:
>>>>
>>>> $ cat /sys/class/ata_device/dev3.0/pio_mode
>>>> XFER_UDMA_7, XFER_UDMA_6, XFER_UDMA_5, XFER_UDMA_4, XFER_MW_DMA_4,
>>>> XFER_PIO_6, XFER_PIO_5, XFER_PIO_4, XFER_PIO_3, XFER_PIO_2, XFER_PIO_1,
>>>> XFER_PIO_0
>>>>
>>>> Using the correct ata_bitfield_name_search() macro fixes that:
>>>>
>>>> $ cat /sys/class/ata_device/dev3.0/pio_mode
>>>> XFER_PIO_4
>>>
>>> Looks good, but Documentation/ABI/testing/sysfs-ata says:
>>
>>    Completely forgot that the sysfs files are documented as ABIs... :-(
>>    Hm, shouldn't that file be added to the libata's entry in MAINTAINERS?

   So what's your opinion on that idea?
>>> pio_mode:       (RO) Transfer modes supported by the device when
>>>                 in PIO mode. Mostly used by PATA device.
>>>
>>> xfer_mode:      (RO) Current transfer mode
>>>
>>> dma_mode:       (RO) Transfer modes supported by the device when
>>>                 in DMA mode. Mostly used by PATA device.
>>>
>>> which seems incorrect/badly worded for pio_mode and dma_mode. Since these
>>> 2 sysfs attributes do not actually device the pio mask (list of supported
>>
>>    Device?
> 
> advertise :)

   Makes sense now. :-)

>>> pio modes) but the pio mode that will be used for that device, we should
>>> reword, no ?
>>
>>    Yes, of course. :-)
>>
>>> What about:
>>>
>>> pio_mode:       (RO) Transfer mode used by the device when
>>>                 in PIO mode. Mostly used by PATA device.
>>>
>>> xfer_mode:      (RO) Current transfer mode
>>>
>>> dma_mode:       (RO) Transfer mode used by the device when
>>>                 in DMA mode. Mostly used by PATA device.
>>
>>    Sounds quite tautological... :-)
>>    What about:
>>
>> {dma|pio}_mode: (RO) {DMA|PIO} transfer mode used by the device.
>>                 Mostly used by PATA devices.
>>
>>    I think this should be done in the same patch. Or would you prefer 2 patches?
> 
> Let's do 2 patches. Not sure if you can find a fixes tag for the doc update

   It'll be the same tag.

> though. But we should not aggregate the 2 attributes as you did. These doc files
> have a defined format and may not be happy with that merged syntax.

   Sorry about that -- I did that just for the mail... :-)

MBR, Sergey