Re: [PATCH 54/64] alim15x3: fix handling of UDMA enable bit

[Bartlomiej Zolnierkiewicz]

Hi Sergei,

On Monday 12 April 2010 03:53:28 pm Sergei Shtylyov wrote:
> Bartlomiej Zolnierkiewicz wrote:
> > From: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
> > Subject: [PATCH] alim15x3: fix handling of UDMA enable bit
> >
> > Clear UDMA enable bit also for PIO modes.
> >   
> 
>    Sorry for late mail but I fail to understand why this was done and 
> what this patch fixes.
> 
> > Based on libata pata_ali host driver.
> 
>    libata has different mode programming code where first always the PIO 
> mode and then DMA mode is set. With IDE core, the order can be 
> different, PIO mode programming shouldn't affect DMA mode bits -- and 
> does not affect it in the other drivers...

This was just a tiny part of larger patchset preparing alim15x3 for
conversion to ide2libata framework and it seems the problem is only
affecting user-initiated transfer mode changes (which are strongly
discouraged anyway) as both libata and IDE core use quite similar
transfer mode programming sequence by default.

However thanks for noticing the issue, I will fix it for both drivers
during the next update of atang tree (unless somebody sends me a patch
sooner).
--
Bartlomiej Zolnierkiewicz
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