Re: ISP1760 driver crashes

From: Alan Stern
Date: Thu Nov 20 2008 - 10:28:32 EST


On Thu, 20 Nov 2008, FUJITA Tomonori wrote:

> We have been used 4GB for long time if dma_mask is zero (I guess we
> use 4GB as kinda the default dma address limit at several places). The
> majority of drivers (such as pci) sets properly dev->dma_mask so the
> patch might not change anything but suddenly changing the
> long-standing rule in an odd way (use BLK_BOUNCE_HIGH if dma_mask is
> zero) doesn't sound a good idea to me.
>
> Why not calling blk_queue_bounce_limit() in the slave_configure hook?
> I think that it's the common way for SCSI LLDs with odd bounce limit.

Thomas, here's a patch to do what Tomonori suggests. Try replacing the
old patch with this one.

Alan Stern


Index: usb-2.6/drivers/usb/storage/scsiglue.c
===================================================================
--- usb-2.6.orig/drivers/usb/storage/scsiglue.c
+++ usb-2.6/drivers/usb/storage/scsiglue.c
@@ -129,6 +129,14 @@ static int slave_configure(struct scsi_d
max_sectors);
}

+ /* Some USB host controllers can't do DMA; they have to use PIO.
+ * They indicate this by setting their dma_mask to NULL. For
+ * such controllers we need to make sure the block layer sets
+ * up bounce buffers in addressable memory.
+ */
+ if (!us->pusb_dev->bus->controller->dma_mask)
+ blk_queue_bounce_limit(sdev->request_queue, BLK_BOUNCE_HIGH);
+
/* We can't put these settings in slave_alloc() because that gets
* called before the device type is known. Consequently these
* settings can't be overridden via the scsi devinfo mechanism. */

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