Messages in this thread | | | Subject | Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of completion | From | Daniel Wagner <> | Date | Mon, 1 Aug 2016 14:26:04 +0200 |
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On 07/31/2016 09:23 AM, Dmitry Torokhov wrote: > On July 30, 2016 9:58:17 AM PDT, "Luis R. Rodriguez" <mcgrof@kernel.org> wrote: >> On Sat, Jul 30, 2016 at 02:42:41PM +0200, Arend van Spriel wrote: >>> On 29-07-16 08:13, Daniel Wagner wrote: >>>> On 07/28/2016 09:01 PM, Bjorn Andersson wrote: >>>>> On Thu 28 Jul 11:33 PDT 2016, Dmitry Torokhov wrote:
>>> + Luis (again) ;-)
That was not on purpose :) My attempt to keep the Cc list a bit shorter was a failure.
>>>>>> Do not quite like it... I'd rather asynchronous request give out >>>>>> firmware status pointer that could be used later on. >>> >>> Excellent. Why not get rid of the callback function as well and have >>> fw_loading_wait() return result (0 = firmware available, < 0 = fail). >>> Just to confirm, you are proposing a new API function next to >>> request_firmware_nowait(), right? >> >> If proposing new firmware_class patches please bounce / Cc me, I've >> recently asked for me to be added to MAINTAINERS so I get these >> e-mails as I'm working on a new flexible API which would allow us >> to extend the firmware API without having to care about the old >> stupid usermode helper at all.
These patches here are a first attempt to clean up a bit of the code around the completion API. As Dmitry correctly pointed out, it makes more sense to go bit further and make the async loading a bit more convenient for the drivers.
> I am not sure why we started calling usermode helper "stupid". We > only had to implement direct kernel firmware loading because udev/stsremd > folks had "interesting" ideas how events should be handled; but having > userspace to feed us data is not stupid.
I was ignorant on all the nasty details around the firmware loading. If I parse Luis' patches correctly they introduce an API which calls kernel_read_file_from_path() asynchronously:
sysdata_file_request_async(..., &cookie) *coookie = async_schedule_domain(request_sysdata_file_work_func(), ..)
request_sysdata_file_work_fun() _sysdata_file_request() fw_get_filesystem_firmware() kernel_read_file_from_path()
sysdata_synchronize_request(&cookie);
Doesn't look like what your asking for.
> If we want to overhaul firmware loading support we need to figure > out how to support case when a driver want to [asynchronously] request > firmware/config/blob and the rest of the system is not ready. Even if we > want kernel to do read/load the data we need userspace to tell kernel > when firmware partition is available, until then the kernel should not > fail the request.
I gather from Luis' blog post and comments that he is on the quest on removing userspace support completely.
Maybe this attempt here could be a step before. Step 1 would be changing request_firmware_nowait() to request_firmware_async so drivers don't have to come up with their own sync primitives, e.g.
cookie = request_firmware_async() fw_load_wait(cookie)
Step 2 could be something more towards sysdata approach.
cheers, daniel
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