lkml.org 
[lkml]   [2012]   [Mar]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[RFC] firmware loader: retry _nowait requests when userhelper is not yet available
From
Date
During resume, the userhelper might not be available. However for
drivers which use the request_firmware_nowait interface, this will
only lead to a pointless WARNING and a device which no longer works
after the resume [since it couldn't get the firmware, because the
userhelper was not available to take the request].

In order to solve this "chicken or egg" dilemma, the code now
retries _nowait requests at one second intervals until the
"loading_timeout" time is up.

---
I'm aware about the previous "request_firmware* in probe" discussions.
Unfortunately, the hardware needs firmware so there is no other way
around it. So please, I just wanted to know what the general opinion
about the idea behind this patch is.
Regards,
Christian

BTW: I'm not on the list, so please keep the 'CC'.
---
drivers/base/firmware_class.c | 24 +++++++++++++++++++++++-
1 files changed, 23 insertions(+), 1 deletions(-)
diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index 6c9387d..9f70096 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -19,6 +19,7 @@
#include <linux/kthread.h>
#include <linux/highmem.h>
#include <linux/firmware.h>
+#include <linux/delay.h>
#include <linux/slab.h>

#define to_dev(obj) container_of(obj, struct device, kobj)
@@ -535,6 +536,11 @@ static int _request_firmware(const struct firmware **firmware_p,

read_lock_usermodehelper();

+ if (nowait && usermodehelper_is_disabled()) {
+ retval = -EBUSY;
+ goto out;
+ }
+
if (WARN_ON(usermodehelper_is_disabled())) {
dev_err(device, "firmware: %s will not be loaded\n", name);
retval = -EBUSY;
@@ -633,7 +639,7 @@ static int request_firmware_work_func(void *arg)
{
struct firmware_work *fw_work = arg;
const struct firmware *fw;
- int ret;
+ int ret, timeout = loading_timeout;

if (!arg) {
WARN_ON(1);
@@ -642,6 +648,22 @@ static int request_firmware_work_func(void *arg)

ret = _request_firmware(&fw, fw_work->name, fw_work->device,
fw_work->uevent, true);
+
+ while (ret == -EBUSY) {
+ /*
+ * Try to retrieve the firmware within the loading timeout.
+ * To stick with the loading timeout convention from above:
+ * loading_timeout = 0 means 'try forever' as well.
+ */
+
+ msleep(1000);
+ ret = _request_firmware(&fw, fw_work->name, fw_work->device,
+ fw_work->uevent, true);
+
+ if (timeout != 0 && timeout-- == 1)
+ break;
+ };
+
fw_work->cont(fw, fw_work->context);

module_put(fw_work->module);
--
1.7.9.1


\
 
 \ /
  Last update: 2012-03-03 21:25    [from the cache]
©2003-2011 Jasper Spaans