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

[Damien Le Moal <damien.lemoal@opensource.wdc.com>]

On 6/7/22 18:49, Sergei Shtylyov wrote:
> 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.

OK. Then let's do code and doc fixes in one patch, not 2.

> 
>> 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


-- 
Damien Le Moal
Western Digital Research