On Fri, Jan 07, 2011 at 01:08:47PM +0100, Johan Hovold wrote:
> On Fri, Jan 07, 2011 at 11:27:18AM +0000, Russell King - ARM Linux wrote:
> > Is this actually an error? Surely for serial devices, this is normal
> > behaviour.
> >
> > At the moment, it makes the console on the machine unusable all the time
> > that the USB device is in use. Obviously, a serial device won't may not
> > have data available for long periods of time to satisfy a pending read.
> > Note that the console is serial, so printk() will have a higher latency
> > than printk() to VGA.
>
> I'd suggest disabling the KERN_NOTICE message in question first. If that
> alone does not help, try enabling debugging in both usb-serial and ftdi_sio.
Done.
Enabling debugging in ftdi_sio isn't going to be useful. With it
enabled, I get a kernel message log very quickly full of:
drivers/usb/serial/ftdi_sio.c: ftdi_process_packet - port 2
and anything else is just going to be swamped out of existence.
With this on, I'm unable to reproduce the problem - I've pasted
"setenv bootargs 'root=/dev/mmcblk0p2 rw mem=512M vmalloc=1G console=ttyO2,115200n8 rootdelay=2'"
about 30 times into minicom and it continues working.
If I disable ftdi_sio debugging, after five pastes of that, it all comes
to a halt again, with wchan as before. If at that point I unplug the USB
cable, I get this:
hub 1-1:1.0: hub_port_status failed (err = -110)
hub 1-1:1.0: hub_port_status failed (err = -110)
hub 1-1:1.0: hub_port_status failed (err = -110)
repeating every six seconds.
diff --git a/drivers/usb/host/isp1760-hcd.c b/drivers/usb/host/isp1760-hcd.c
index bdba8c5..00fd7ba 100644
--- a/drivers/usb/host/isp1760-hcd.c
+++ b/drivers/usb/host/isp1760-hcd.c
@@ -1049,17 +1049,6 @@ static void do_atl_int(struct usb_hcd *usb_hcd)
if (!nakcount && (dw3 & DW3_QTD_ACTIVE)) {
u32 buffstatus;
- /*
- * NAKs are handled in HW by the chip. Usually if the
- * device is not able to send data fast enough.
- * This happens mostly on slower hardware.
- */
- printk(KERN_NOTICE "Reloading ptd %p/%p... qh %p read: "
- "%d of %zu done: %08x cur: %08x\n", qtd,
- urb, qh, PTD_XFERRED_LENGTH(dw3),
- qtd->length, done_map,
- (1 << queue_entry));
-
/* RL counter = ERR counter */
dw3 &= ~(0xf << 19);
dw3 |= rl << 19;
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 2dec500..96e359c 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -30,7 +30,7 @@
/* to talk to the device */
/* Thanx to gkh and the rest of the usb dev group for all code I have
assimilated :-) */
-
+#define DEBUG
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 6954de5..2aca55c 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -16,7 +16,7 @@
* driver
*
*/
-
+#define DEBUG
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
--
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