Hello,
On Thu, 3 Jan 2002, Alan Cox 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.
>
Maybe this is more appropriate then :)
It tells the scsi scanner to always use DMA safe memory when doing its
INQUIRY commands...
On the O2, kernel is running in cacheable, non-coherent memory. kmalloc,
with GFP_DMA flag will return a piece of uncacheable memory which is safe
for I/O with devices.
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;
