Messages in this thread | | | Date | Tue, 06 Mar 2012 01:42:54 +0530 | From | "Srivatsa S. Bhat" <> | Subject | Re: [RFC] firmware loader: retry _nowait requests when userhelper is not yet available |
| |
[ Adding more Cc's. ]
On 03/04/2012 01:52 AM, Christian Lamparter wrote:
> 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);
| |