Messages in this thread Patch in this message | | | Subject | [RFC] firmware loader: retry _nowait requests when userhelper is not yet available | From | Christian Lamparter <> | Date | Sat, 3 Mar 2012 21:22:36 +0100 |
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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
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