RE: Linux 4.4.4 [regression]

[Deucher, Alexander]

> -----Original Message-----
> From: linus971@xxxxxxxxx [mailto:linus971@xxxxxxxxx] On Behalf Of Linus
> Torvalds
> Sent: Monday, March 07, 2016 11:21 AM
> To: JÃrg-Volker Peetz; Dave Airlie; DRI mailing list
> Cc: Greg KH; Linux Kernel Mailing List; Andrew Morton; stable; lwn@xxxxxxx;
> Jiri Slaby; Deucher, Alexander
> Subject: Re: Linux 4.4.4 [regression]
> 
> On Mon, Mar 7, 2016 at 6:20 AM, JÃrg-Volker Peetz <jvpeetz@xxxxxx>
> wrote:
> >
> > This same problem with X does happen in 4.5-rc7. And removing the line
> > introduced by patch b36e52c44ce6728824546d8b5f05b844cede96f1 makes
> X go again on
> > my laptop.
> 
> Ok, so that's dbb17a21c131eca94eb31136eee9a7fe5aff00d9 in mainline.
> 
> Dave, Alex: that commit makes JÃrg-Volker's HP Pavilion dv7 with
> hybrid graphics (AMD HD 4200 - AMD 5400) unable to run X. No
> suspend/resume in sight, just starting X hangs.
> 
> I'd guess it's the "radeon_switcheroo_set_state()" craziness (based on
> that hybrid graphics thing), but we need to do something since this is
> a regression.
> 
> Just revert for now? Or do you have other suggestions for JÃrg-Volker to
> test?

Can you attach your dmesg output?

> 
> Maybe that call to drm_helper_hpd_irq_event() should be purely in the
> real resume path?
> 
> Or maybe there is something that the switcheroo code does that just
> interacts badly with the code in drm_helper_hpd_irq_event()? Deadlock
> on mode_config.mutex or something?
> 
> I suspect we just need to revert, but if somebody who knows the code
> sees some obvious fix, holler quickly, please.

Yes, It's probably something related to switcheroo.  Does the attached patch help?

Alex

Attachment: 0001-drm-radeon-selectively-call-drm_helper_hpd_irq_event.patch
Description: 0001-drm-radeon-selectively-call-drm_helper_hpd_irq_event.patch