Commit 509426bd authored Dec 20, 2009 by Bartlomiej Zolnierkiewicz Committed by Jeff Garzik Dec 20, 2009

pata_cmd64x: fix overclocking of UDMA0-2 modes



adev->dma_mode stores the transfer mode value not UDMA mode number
so the condition in cmd64x_set_dmamode() is always true and the higher
UDMA clock is always selected.  This can potentially result in data
corruption when UDMA33 device is used, when 40-wire cable is used or
when the error recovery code decides to lower the device speed down.

The issue was introduced in the commit 6a40da02 ("libata cmd64x: whack
into a shape that looks like the documentation") which goes back to
kernel 2.6.20.

Cc: stable@kernel.org
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

parent 06393afd

drivers/ata/pata_cmd64x.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -219,7 +219,7 @@ static void cmd64x_set_dmamode(struct ata_port ap, struct ata_device adev)
		regU \|= udma_data[adev->dma_mode - XFER_UDMA_0] << shift;
		/* Merge the control bits */
		regU \|= 1 << adev->devno; /* UDMA on */
		if (adev->dma_mode > 2) /* 15nS timing */
		if (adev->dma_mode > XFER_UDMA_2) /* 15nS timing */
		regU \|= 4 << adev->devno;
		} else {
		regU &= ~ (1 << adev->devno); /* UDMA off */