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

  That turned to be the requirement of the CF spec... :-/

>>>>> id[ATA_ID_CONFIG]        = 0x044A

   CF 4.x lists this value as "CF preferred altrernate", along with 0x0040.

>>>>   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.
>> id[ATA_ID_COMMAND_SET_2] = 0 /* For my Kingston 1Gb CF card, kernel 
>> v2.6.28.1 */
>    Then I guess we need a new quirk. :-/

   BTW, CF 4.x says that the drive reporting word 0 bits 12:15 as 0 "is 
required to support for the CFA command set and report that in bit 2 of 
Word 83". So thank Kingston for being CF incompatible. :-)

MBR, Sergei