Re: [parisc-linux] Re: Why toggle_bounce only for disks?

[James Bottomley <James.Bottomley@SteelEye.com>]

On Fri, 2005-08-19 at 12:21 +0200, Jens Axboe wrote:
> Because not bouncing is a performance optimization and I only did the
> work on ide-cd to allow it. Your patch breaks ide-cd on highmem i386
> machines, so it's not acceptable.
> 
> Tells us more about this crash instead, I'm pretty sure you are working
> around another issue (your io-mmu code, is it hardware or software?)
> somehwere with this patch.

OK, so the particular fix is wrong; but the logic in ide_toggle_bounce()
is also incorrec.  Our problem is not that we don't want to bounce
highmem in ide-cd, it's that this is a parisc system with an IOMMU and
doesn't have any highmem to begin with.

we need ide_toggle_bounce to return BLK_BOUNCE_ANY always if
PCI_DMA_BUS_IS_PHYS is not set.

James

diff --git a/drivers/ide/ide-lib.c b/drivers/ide/ide-lib.c
--- a/drivers/ide/ide-lib.c
+++ b/drivers/ide/ide-lib.c
@@ -410,10 +410,10 @@ void ide_toggle_bounce(ide_drive_t *driv
 {
 	u64 addr = BLK_BOUNCE_HIGH;	/* dma64_addr_t */
 
-	if (on && drive->media == ide_disk) {
-		if (!PCI_DMA_BUS_IS_PHYS)
-			addr = BLK_BOUNCE_ANY;
-		else if (HWIF(drive)->pci_dev)
+	if (!PCI_DMA_BUS_IS_PHYS)
+		addr = BLK_BOUNCE_ANY;
+	else if (on && drive->media == ide_disk) {
+		if (HWIF(drive)->pci_dev)
 			addr = HWIF(drive)->pci_dev->dma_mask;
 	}