hi,
James Bottomley wrote:
On Mon, 2008-10-27 at 12:35 +0100, Matthias Kaehlcke wrote:
James Bottomley wrote:
On Fri, 2008-10-24 at 09:05 +0200, Matthias Kaehlcke wrote:
inserting a Verbatim 4GB USB stick in a ep9307 based device running
kernel 2.6.27 results in the following Oops:
[42949395.050000] usb 1-3: new full speed USB device using ep93xx-ohci
and address 2
[42949395.250000] usb 1-3: configuration #1 chosen from 1 choice
[42949395.260000] scsi0 : SCSI emulation for USB Mass Storage devices
[42949395.270000] usb 1-3: New USB device found, idVendor=13fe,
idProduct=1f23
[42949395.280000] usb 1-3: New USB device strings: Mfr=1, Product=2,
SerialNumber=3
[42949395.280000] usb 1-3: Product: STORE N GO
[42949395.300000] usb 1-3: Manufacturer: Verbatim
[42949395.310000] usb 1-3: SerialNumber: 078813D90478
[42949400.280000] Unable to handle kernel NULL pointer dereference at
virtual address 00000003
[42949400.280000] pgd = c0648000
[42949400.300000] [00000003] *pgd=c0647031, *pte=00000000, *ppte=00000000
[42949400.300000] Internal error: Oops: 13 [#1] PREEMPT
[42949400.300000] Modules linked in:
[42949400.300000] CPU: 0 Not tainted (2.6.27 #3)
[42949400.300000] PC is at scsi_calculate_bounce_limit+0x3c/0x44
Best guess is this line:
if (host_dev && host_dev->dma_mask)
bounce_limit = *host_dev->dma_mask;
I'd guess host_dev->dma_mask contains 0x3 ... could this be some sort of
ARM setup problem?
thanks for having a look!
i could figure out the difference between 2.6.26.3 and 2.6.27 that
triggers the Oops:
diff -u linux-2.6.26.3/include/asm-arm/pci.h
linux-2.6.27/arch/arm/include/asm/pci.h
...
@@ -30,7 +30,7 @@
* The networking and block device layers use this boolean for bounce
* buffer decisions.
*/
-#define PCI_DMA_BUS_IS_PHYS (0)
+#define PCI_DMA_BUS_IS_PHYS (1)
/*
* Whether pci_unmap_{single,page} is a nop depends upon the
...
this change affects the following piece of code in
scsi_calculate_bounce_limit():
if (!PCI_DMA_BUS_IS_PHYS)
return BLK_BOUNCE_ANY;
host_dev = scsi_get_device(shost);
if (host_dev && host_dev->dma_mask)
bounce_limit = *host_dev->dma_mask;
host_dev->dma_mask is 0xffffffff and we try to dereference the pointer
So the host_dev is some type of arm platform device? If so, it's got
it's dma_mask set up wrongly. it's a pointer in struct device and is
supposed to point to the real u64 quantity located within the actual
enclosing device.
thanks a lot for the pointer, i think i fixed the problem:
--- linux-2.6.27.org/arch/arm/mach-ep93xx/core.c 2008-10-10
00:13:53.000000000 +0200
+++ linux-2.6.27/arch/arm/mach-ep93xx/core.c 2008-10-27
17:00:42.000000000 +0100
@@ -26,6 +26,7 @@
#include <linux/serial_core.h>
#include <linux/device.h>
#include <linux/mm.h>
+#include <linux/dma-mapping.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/delay.h>
@@ -450,12 +451,14 @@
},
};
+static u64 ep93xx_ohci_dmamask = DMA_BIT_MASK(32);
+
static struct platform_device ep93xx_ohci_device = {
.name = "ep93xx-ohci",
.id = -1,
.dev = {
- .dma_mask = (void *)0xffffffff,
- .coherent_dma_mask = 0xffffffff,
+ .dma_mask = &ep93xx_ohci_dmamask,
+ .coherent_dma_mask = DMA_BIT_MASK(32),
},
.num_resources = ARRAY_SIZE(ep93xx_ohci_resources),
.resource = ep93xx_ohci_resources,
i'm going to submit this patch to mainline if there are no objections
(apologizes to the scsi ppl for spamming your list with an issue that
turns out not to be directly related to scsi)
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