Commit 032af1ce authored by Alan's avatar Alan Committed by Jeff Garzik
Browse files

libata-core: Fix simplex handling 



The initial simplex handling code is fooled if you suspend and resume.
This also causes problems with some single channel controllers which
claim to be simplex.

The fix is fairly simple, instead of keeping a flag to remember if we
gave away the simplex channel we remember the actual owner. As the owner
is always part of the host_set we don't even need a refcount.

Knowing the owner also means we can reassign simplex DMA channels in
future hotplug code etc if we need to

Signed-off-by: default avatarAlan Cox <alan@redhat.com>
(and a signed-off for the patch I sent before while I remember)
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 562aa1d4

drivers/ata/libata-core.c

+2 −3
Original line number Diff line number Diff line
@@ -2556,12 +2556,11 @@ int ata_set_mode(struct ata_port *ap, struct ata_device **r_failed_dev) 
	 * host channels are not permitted to do so.

	 */

	if (used_dma && (ap->host->flags & ATA_HOST_SIMPLEX))

		ap->host->simplex_claimed = 1;

		ap->host->simplex_claimed = ap;



	/* step5: chip specific finalisation */

	if (ap->ops->post_set_mode)

		ap->ops->post_set_mode(ap);



 out:

	if (rc)

		*r_failed_dev = dev;
@@ -3444,7 +3443,7 @@ static void ata_dev_xfermask(struct ata_device *dev) 
			       "device is on DMA blacklist, disabling DMA\n");

	}



	if ((host->flags & ATA_HOST_SIMPLEX) && host->simplex_claimed) {

	if ((host->flags & ATA_HOST_SIMPLEX) && host->simplex_claimed != ap) {

		xfer_mask &= ~(ATA_MASK_MWDMA | ATA_MASK_UDMA);

		ata_dev_printk(dev, KERN_WARNING, "simplex DMA is claimed by "

			       "other device, disabling DMA\n");

include/linux/libata.h

+1 −2
Original line number Diff line number Diff line
@@ -403,8 +403,7 @@ struct ata_host { 
	void			*private_data;

	const struct ata_port_operations *ops;

	unsigned long		flags;

	int			simplex_claimed;	/* Keep seperate in case we

							   ever need to do this locked */

	struct ata_port		*simplex_claimed;	/* channel owning the DMA */

	struct ata_port		*ports[0];

};

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