alim15x3: fix handling of UDMA enable bit
in [Kernel]
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From: Sergei Shtylyov on 12 Apr 2010 10:00 Bartlomiej Zolnierkiewicz wrote: > From: Bartlomiej Zolnierkiewicz <bzolnier(a)gmail.com> > 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... MBR, Sergei -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Bartlomiej Zolnierkiewicz on 13 Apr 2010 11:20 Hi Sergei, On Monday 12 April 2010 03:53:28 pm Sergei Shtylyov wrote: > Bartlomiej Zolnierkiewicz wrote: > > From: Bartlomiej Zolnierkiewicz <bzolnier(a)gmail.com> > > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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