At Tue, 09 Dec 2014 18:56:07 +0200, Imre Deak wrote: > > On Tue, 2014-12-09 at 11:03 +0100, Daniel Vetter wrote: > > On Tue, Dec 09, 2014 at 10:59:54AM +0200, Imre Deak wrote: > > > On Mon, 2014-12-08 at 21:14 +0100, Daniel Vetter wrote: > > > > On Mon, Dec 08, 2014 at 06:42:04PM +0200, Imre Deak wrote: > > > > > The current hda/i915 interface to enable/disable power wells and query > > > > > the CD clock rate is based on looking up the relevant i915 module > > > > > symbols from the hda driver. By using the component framework we can get > > > > > rid of some global state tracking in the i915 driver and pave the way to > > > > > fully decouple the two drivers: once support is added to enable/disable > > > > > the HDMI functionality dynamically in the hda driver, it can bind/unbind > > > > > itself from the i915 component master, without the need to keep a > > > > > reference on the i915 module. > > > > > > > > > > This also gets rid of the problem that currently the i915 driver exposes > > > > > the interface only on HSW and BDW, while it's also needed at least on > > > > > VLV/CHV. > > > > > > > > Awesome that you're tackling this, really happy to see these hacks go. > > > > Unfortunately I think it's upside down: hda should be the component master > > > > and i915 should only register a component. > > > > > > > > Longer story: The main reason for the component helpers is to be able to > > > > magically delay registering the main/master driver until all the > > > > components are loaded. Otherwise -EDEFER doesn't work and also the > > > > suspend/resume ordering this should result in. Master here means whatever > > > > userspace eventually sees as a device node or similar, component is > > > > anything really that this userspace interfaces needs to function > > > > correctly. > > > > > > EDEFER doesn't solve the suspend/resume ordering, at least not in the > > > general async s/r case. In any case I don't see a problem in making the > > > hda component the master and I think it's more logical that way as you > > > said, so I changed that. > > > > Yeah for full async s/r we're screwed as-is. But see below for some crazy > > ideas. > > > > I think what we need here is then: > > > > - Put the current azx_probe into the master_bind callback. The new > > > > azx_probe will do nothing else than register the master component and > > > > the component match list. To do so it checks the chip flag and if it > > > > needs to cooperate with i915 it registers one component match for that. > > > > The master_bind (old probe) function calls component_bind_all with the > > > > hda_intel pointer as void *data parameter. > > > > > > I'm not sure this is the best way since by this the i915 module would > > > need to be pinned even when no HDMI functionality is used. I think a > > > better way would be to let the probe function run as now and > > > init/register all the non-HDMI functionality. Then only the HDMI > > > functionality would be inited/registered from the bind/unbind hooks. > > > > Hm, I wasn't sure whether alsa allows this and thought we need i915 anyway > > to be able to load the driver. But if we can defer just the hdmi part. > > > > > But we could go either way even as a follow-up to this patchset. > > > > > > > - i915 registers a component for the i915 gfx device. It uses the > > > > component device to get at i915 sturctures and fills the dev+ops into > > > > the hda_intel pointer it gets as void *data. > > > > > > > > Stuff we then should do on top: > > > > - Add deferred probing to azx_probe: Only when all components are there > > > > should it actually register. This will take care of all the module load > > > > order mess. > > > > > > I agree that we should only register user interfaces when everything is > > > in place. But I'm not sure deferred probe is the best, we could do > > > without it by registering HDMI from the component bind hook. > > > > It's mostly a question whether alsa does support delayed addition of > > interface parts. DRM most definitely does not (except for recently added > > dp mst connector hotplug). But I guess if the current driver already > > delays registering the hdmi part then we're fine. I'm not sure about > > whether it's really safe - I spotted not a lot of locking really to make > > sure there's no races between i915 loading and userspace trying to access > > the hdmi side. > > Ok, I'm not sure either. If that's not possible, I agree EDEFER would be > the best and with that we could also get rid of the request_module() we > need now. The probe of HD-audio driver is done in a work anyway, so changing the code to sync with component should be feasible. I'm off today (and yesterday was a Christmas party :), so had little time for review so far. Will check the series tomorrow. thanks, Takashi _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
