Re: [PATCH] pata_it821x: sync with IDE it821x driver

From: Tejun Heo
Date: Sat Jun 09 2007 - 01:59:38 EST


Bartlomiej Zolnierkiewicz wrote:
> * (partially) fix DMA in RAID mode
> Code intended to check DMA status was checking DMA command register.
> Moreover firmware seems to "forget" to set DMA capable bit for the
> slave device (at least in RAID mode but without ITE RAID volumes) so
> check device ID for DMA capable bit when deciding whether to use DMA
> and remove DMA status check completely.
> Thanks to Pavol Šimo for the bugreport and testing the initial fix.

Ah... This is the mysterious mwdma configuration in smart mode, right?
Thanks for fixing this.

> This change unfortunately still doesn't fix DMA in RAID mode (which
> works fine with IDE it821x) but Alan is working on the missing pieces
> (pata_it821x vs libata EH issues).

This is the lbal/nsect SRST problem, right?

> @@ -258,8 +259,14 @@ static void it821x_passthru_set_piomode(
> static const u8 pio_want[] = { ATA_66, ATA_66, ATA_66, ATA_66, ATA_ANY };
> struct it821x_dev *itdev = ap->private_data;
> + struct ata_device *pair = ata_dev_pair(adev);
> int unit = adev->devno;
> - int mode_wanted = adev->pio_mode - XFER_PIO_0;
> + int mode_wanted = adev->pio_mode;
> +
> + if (pair && adev->pio_mode > pair->pio_mode)
> + mode_wanted = pair->pio_mode;
> +
> + mode_wanted -= XFER_PIO_0;

I think this is better done by mode_filter callback which is guaranteed
to be called before any actual mode configuration is performed and in
device order (master then slave).


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