Re: [PATCH] ide: motherboard-info based blacklist for ide-dma

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello, I wrote:

>>>>>>>> True.  However it should be possible to handle it correctly by 
>>>>>>>> adding
>>>>>>>> the
>>>>>>>> DMA quirk to the respective host drivers (seems to be 
>>>>>>>> via82cxxx.c in
>>>>>>>> case of
>>>>>>>> IEI PCISA-C3/EDEN).

>>>>>>>  Yeah, this seems a viable approach...

>>>>>>>> Kirill, could you please look into adding such quirk to via82cxxx
>>>>>>>> instead?

>>>>>>>> [ It seems the best place to add it would be via_init_one() as we
>>>>>>>> could just

>>>>>>>  No, not really -- the issue is not at all as simple as this patch
>>>>>>> tried to present it. Looking at its "Quick Startup Reference"
>>>>>>> (http://f.ipc2u.ru/files/add/doc/496/M_PCISA-C800EV_ENG.pdf), the 
>>>>>>> EPIC
>>>>>>> board has *two* normal IDE connectors in addition to the CF slot
>>>>>>> (connected to the secondary port -- and it seems possible that a 
>>>>>>> hard
>>>>>>> drive can be connected to the same port as CF), so the right place
>>>>>>> seems to rather be in [mu]dma_filter() methods -- and the decision
>>>>>>> should be strictly based on the drive type indicating CF, i.e. by
>>>>>>> calling ata_id_is_cfa().

>>> I have tried my old Trancend 64Mb, RamStar 521Mb and NCP 64Mb cards. 
>>> My old cards returned right id[ATA_ID_CONFIG] = 0x848A.

>>> But I have to use Kingston CF Card 1Gb 2008.
>>> ata_id_is_cfa() returns 0 for it and
>>> id[ATA_ID_MAJOR_VER]    = 0
>>> id[ATA_ID_CONFIG]        = 0x044A

>>    That seems non-standard CF as ATA specifies that it must have 
>> 0x848A there.

>>> I have only CF+ specification revision 2.0,  but I've found in wiki:

>>    Try googling for cfspc_41.pdf (and other versions), you'll be 
>> surprised in a good way. ;-)

>>> (http://en.wikipedia.org/wiki/CompactFlash#CF.2B_specification_revisions) 

>>> "... While the current revision 4.1 from 2004 works only in ATA mode, 
>>> ..."

>>> So I have reached an impasse. How to identify modern CF cards?

>>    Hm, I should consult the specs...

>    ATA/PI-7 rev. 4b has this in 4.10:

> Devices reporting the value 848Ah in IDENTIFY DEVICE data word 0 or 
> devices having bit 2 of IDENTIFY DEVICE data word 83 set to one shall 
> support the CFA feature Set. If the CFA feature set is implemented, all 
> five commands shall be implemented.

>    Alan, looks like the libata's CF criterion needs to be enhanced.

    Oops, my bad -- I should've looked first. :-<
    Dmitry, just use the modern version of ata_id_is_cfa().

MBR, Sergei