On Thu, 3 Jan 2002, Ralf Baechle wrote:
> On Thu, Jan 03, 2002 at 10:51:51PM +0100, Vivien Chappelier wrote:
>
> > > > This tells the aic7xxx to use DMA safe memory for I/O.
> > >
> > > That seems totally inappropriate. The unchecked dma option is for
> > > ancient ISA DMA controllers that didnt do the 16Mb check. If you
> > > find you need it debug your pci remapper
> >
> > This is used when scaning for devices (drivers/scsi/scsi_scan.c) . When
> > this flag is not set, the code uses memory from the stack (unsigned char
> > scsi_result0[256]; in scan_scsis) instead of kmallocating it DMA safe as
> > it should on non-coherent systems. Maybe this is the thing to change?
>
> Indeed, it is. I thought this one died ages ago.
Here is a patch to fix that then. It forces allocation of DMA safe
memory in any case. I've not looked at the PPC64 patch however.
regards,
Vivien Chappelier.
--- linux/drivers/scsi/scsi_scan.c Thu Dec 20 18:31:09 2001
+++ linux.patch/drivers/scsi/scsi_scan.c Fri Jan 4 13:17:31 2002
@@ -283,7 +283,6 @@
unsigned int lun;
unsigned int max_dev_lun;
unsigned char *scsi_result;
- unsigned char scsi_result0[256];
Scsi_Device *SDpnt;
Scsi_Device *SDtail;
unsigned int sparse_lun;
@@ -305,8 +304,7 @@
scsi_initialize_queue(SDpnt, shpnt);
SDpnt->request_queue.queuedata = (void *) SDpnt;
/* Make sure we have something that is valid for DMA purposes */
- scsi_result = ((!shpnt->unchecked_isa_dma)
- ? &scsi_result0[0] : kmalloc(512, GFP_DMA));
+ scsi_result = kmalloc(512, GFP_DMA);
}
if (scsi_result == NULL) {
@@ -463,7 +461,7 @@
}
/* If we allocated a buffer so we could do DMA, free it now */
- if (scsi_result != &scsi_result0[0] && scsi_result != NULL) {
+ if (scsi_result != NULL) {
kfree(scsi_result);
} {
Scsi_Device *sdev;
