Hello folks,
(It's been a few years since I've submitted any kernel patches, my
etiquette may be rusty. Feel free to flame me. This was not sent to
the listed maintainer as I don't think Tapio's been heard from in some
time. Correct me if I'm wrong :-)
It's become apparent as machines get faster that the emagic kernel
firmware loaders (based on the ezusb loader) have a reset race. a
400MHz TiBook never tripped it, but a 2GHz Pentium M seems to hit it
about 30% of the time. The bug is seen as a hung USB box and the
kernel error:
drivers/usb/misc/emi62.c: emi62_load_firmware - error loading firmware:
error = -110
The patch below inserts a delay after deasserting reset to allow the
box to settle before a new command is issued. This affects only device
startup. It's against 2.6.27-rc3, but should apply to any 2.6 kernel;
I don't think the loader has changed for a long time.
(A side note; I notice the firmware loader is using a rather old
firmware version for both devices. Several relatively harmless but
annoying bugs have since been fixed... how was the firmware from this
device originally extracted? Was it taken from a device driver
belonging to another OS, or was it provided as a hexdump from emagic?)
Monty
diff -brwu linux-2.6.17-rc3/drivers/usb/misc/emi26.c
linux-2.6.17-rc3-monty/drivers/usb/misc/emi26.c
--- linux-2.6.17-rc3/drivers/usb/misc/emi26.c 2006-04-26
22:19:25.000000000 -0400
+++ linux-2.6.17-rc3-monty
/drivers/usb/misc/emi26.c 2006-05-02
22:22:50.000000000 -0400
@@ -15,6 +15,7 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/usb.h>
+#include <linux/delay.h>
#define MAX_INTEL_HEX_RECORD_LENGTH 16
typedef struct _INTEL_HEX_RECORD
@@ -114,6 +115,7 @@
/* De-assert reset (let the CPU run) */
err = emi26_set_reset(dev,0);
+ msleep(250); /* let device settle */
/* 2. We upload the FPGA firmware into the EMI
* Note: collect up to 1023 (yes!) bytes and send them with
@@ -157,6 +159,7 @@
err("%s - error loading firmware: error = %d", __FUNCTION__, err);
goto wraperr;
}
+ msleep(250); /* let device settle */
/* 4. We put the part of the firmware that lies in the external RAM into the EZ-USB */
for (i=0; g_Firmware[i].type == 0; i++) {
@@ -192,6 +195,7 @@
err("%s - error loading firmware: error = %d", __FUNCTION__, err);
goto wraperr;
}
+ msleep(250); /* let device settle */
/* return 1 to fail the driver inialization
* and give real driver change to load */
diff -brwu linux-2.6.17-rc3/drivers/usb/misc/emi62.c
linux-2.6.17-rc3-monty/drivers/usb/misc/emi62.c
--- linux-2.6.17-rc3/drivers/usb/misc/emi62.c 2006-04-26
22:19:25.000000000 -0400
+++ linux-2.6.17-rc3-monty
/drivers/usb/misc/emi62.c 2006-05-02
22:54:40.000000000 -0400
@@ -15,6 +15,7 @@
#include <linux/init.h>
#include <linux/module.h>
#include <linux/usb.h>
+#include <linux/delay.h>
#define MAX_INTEL_HEX_RECORD_LENGTH 16
typedef struct _INTEL_HEX_RECORD
@@ -123,6 +124,7 @@
/* De-assert reset (let the CPU run) */
err = emi62_set_reset(dev,0);
+ msleep(250); /* let device settle */
/* 2. We upload the FPGA firmware into the EMI
* Note: collect up to 1023 (yes!) bytes and send them with
@@ -166,6 +168,7 @@
err("%s - error loading firmware: error = %d", __FUNCTION__, err);
goto wraperr;
}
+ msleep(250); /* let device settle */
/* 4. We put the part of the firmware that lies in the external RAM into the EZ-USB */
@@ -228,6 +231,7 @@
err("%s - error loading firmware: error = %d", __FUNCTION__, err);
goto wraperr;
}
+ msleep(250); /* let device settle */
kfree(buf);
-
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