Re: [PATCH] Fix DMA on Dreamcast

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



"Peter Bortas" <[email protected]> writes:

> On 7/21/07, Adrian McMenamin <[email protected]> wrote:
>> On 21/07/07, Peter Bortas <[email protected]> wrote:
>>
>> >
>> > Sidenote: Does Linux handle the Dreamcast DMA errata?
>> >
>>
>> You need to explain what you mean (at least to me!).
>>
>> If you mean will it degrade gracefully - not without this patch if set
>> to the (correct) defconfig. With iffy settings it will.
>
> If I remember correctly (and that's a big if since I last looked at it
> in 2001) some revisions of the Dreamcast hardware would sporadically
> lock up if you scheduled a new DMA request to quickly after a previous
> one, even if you checked the ready bit. It's worked around by a delay
> of X microseconds as recommended by Sega engineers. I don't remember
> the value of X, nor where exactly in the flow this workaround should
> be applied.
>
> Adding Marcus in case he has a better memory than me.


I don't remeber any such delay.  Are you sure you're not thinking
about the G2 bus problem (where accesses need to be programatically
serialized, whether they are PIO or DMA)?


  // Marcus


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux