Hi Tuomas,

sending commands to the disk over DMA does work fine indeed. It's
receiving extended message bytes that does require additional
handshake which is not present in your zorro_esp_pio_cmd() function
that you probably used for testing.

I will add these handshake bits into your PIO function if I can't make
Finn's more generic work in the general case (i.e. for boards where we
haven't got th DMA interface sorted out yet).

Cheers,

  Michael


On Fri, Dec 15, 2017 at 9:34 PM, Vainikka Tuomas
<[email protected]> wrote:
> Hello,
>
> Just bear in mind that there was no need for the PIO transfers when the TCQ 
> was hacked off. Commands over DMA worked fine then at least on my Blizzard 
> SCSI-IV...
>
> -Tuomas
>
> ________________________________________
> From: Michael Schmitz <[email protected]>
> Sent: 14 December 2017 20:40
> To: Vainikka Tuomas
> Cc: Geert Uytterhoeven; linux-m68k
> Subject: Re: m68k v3.16 status update
>
> Hi Tuomas,
>
> fair enough - I'll get the PIO code tested by forcing PIO transfers on
> elgar, and submit the driver for review once that's done. Maybe
> someone else has a chance to test the fix in the meantime.
>
> Cheers,
>
>   Michael
>
>
> On Fri, Dec 15, 2017 at 1:07 AM, Vainikka Tuomas
> <[email protected]> wrote:
>> Hello,
>>
>> I do have the hardware, but unfortunately I do not have the time to test it.
>>
>> -Tuomas
>> ________________________________________
>> From: [email protected] <[email protected]> on 
>> behalf of Michael Schmitz <[email protected]>
>> Sent: 14 December 2017 06:47
>> To: Tuomas Vainikka
>> Cc: Geert Uytterhoeven; linux-m68k
>> Subject: Re: m68k v3.16 status update
>>
>> Tuomas,
>>
>> are you still in the position to test tagged queue messages on Zorro ESP
>> hardware?
>>
>> I've modified the Zorro ESP driver based on the work Finn Thain did for
>> the Mac ESP driver (handling message in transfer by PIO, with special
>> handshaking provisions for the message in case) and tried to test this
>> on elgar (CyberStorm I ESP) but the original bug does not show up there.
>> Might be to do with the SCSI disk used, or the CyberStorm I board.
>>
>> Might be better to test the new code on your hardware where we know the
>> bug happened in the first place.
>>
>> Cheers,
>>
>>         Michael
>>
>> Am 09.08.2014 um 18:45 schrieb Tuomas Vainikka:
>>> On 09.08.2014 01:25, Michael Schmitz wrote:
>>>> Hi Tuomas,
>>>>>>
>>>>>> There's still the Amiga Zorro ESP patch out in limbo - DaveM
>>>>>> suggested a change to enable SCSI-2 features to help with extended
>>>>>> message bytes but that did not work as intended. Haven't had time to
>>>>>> follow that one up. Tuomas' fix to the driver to bypass DMA for
>>>>>> message in works OK though - do you want it submitted back to
>>>>>> linux-scsi as is, or wait for a perfect solution (pun on me ...)?
>>>>>>
>>>>>>
>>>>> Just to refresh your memory, the final fix was not to bypass DMA at
>>>>> any level (I did that for the command transfer, but that didn't
>>>>> help), but to have a dedicated slave_configure() function in the
>>>>> Amiga Zorro ESP driver that would not enable TCQ.
>>>>
>>>> You guessed right about memory failing me - it wasn't about DMA in the
>>>> end (for some reason, I seem to have DMA stuck in my mind at the
>>>> moment), Do you see any other avenues to try and enable tagged
>>>> commands in the ESP chip? We tried one config register only so far...
>>>>
>>> I think I've tested almost all possible register settings for the chip,
>>> but it occurred to me that it is not enough to enable some chip features
>>> by flipping bits. The code in esp_scsi would need to be modified to
>>> handle the behaviour of these enabled features also.
>>>
>>> So, rethinking the code in esp_scsi would be one option.
>>>
>>> The second possibility is that I have a buggy chip in my setup. Removing
>>> a sticker from my SCSI-board revealed the chip to be an AMD AM53CF94.
>>> There are different versions of the SCSI-boards out there with different
>>> chips; NCR, AMD, and QLogic, so if we had more people testing the driver
>>> we would find out if the chip is actually the problem. (Is anyone even
>>> testing the ISA/PCI cards that use esp_scsi?)
>>>
>>> Those are my suggestions at the TCQ problem.
>>>
>>> But do we really need TCQ?
>>>
>>> -Tuomas
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