On Thu, Sep 13, 2018 at 03:35:36PM +0200, Takashi Iwai wrote: > On Thu, 13 Sep 2018 15:27:16 +0200, Jian-Hong Pan wrote: > > 2018-09-13 14:56 GMT+08:00 Takashi Iwai <tiwai@xxxxxxx>: > > > The recent change of vga_switcheroo allowed the runtime PM for > > > HD-audio on AMD GPUs, but this also resulted in a regression. When > > > the HD-audio controller driver gets runtime-suspended, HD-audio link > > > is turned off, and the hotplug notification is ignored. This leads to > > > the inconsistent audio state (the connection isn't notified and ELD is > > > ignored). > > > > > > The best fix would be to implement the proper ELD notification via the > > > audio component, but it's still not ready. As a quick workaround, > > > this patch adds the check of runtime_idle and allows the runtime > > > suspend only when the vga_switcheroo is bound with discrete GPU. > > > That is, a system with a single GPU and APU would be again without > > > runtime PM to keep the HD-audio link for the hotplug notification and > > > ELD read out. > > > > > > Also, the codec->auto_runtime_pm flag is set only for the discrete GPU > > > at the time GPU gets bound via vga_switcheroo (i.e. only dGPU is > > > forcibly runtime-PM enabled), so that APU can still get the ELD > > > notification. > > > > > > For identifying which GPU is bound, a new vga_switcheroo client > > > callback, gpu_bound, is implemented. The vga_switcheroo simply calls > > > this when GPU is bound, and tells whether it's dGPU or APU. > > > > Tested-by: Jian-Hong Pan <jian-hong@xxxxxxxxxxxx> > > Thanks. I should put you also as the original reporter. > > Lukas, could you check the vga_switcheroo change whether it's > acceptable? I looked over it this morning and didn't get every little detail, e.g. why chip->running = 0 in azx_free() (seems like an unrelated change, but I'm not sure). But I do understand the idea underlying the patch and it LGTM. It's somewhat regrettable that we have to make things more complicated again to properly differentiate between integrated and discrete GPUs. I wish we could later on come up with a scheme that is lightweight and easy to follow. Obviously, such a scheme will likely not be eligible as a fix for 4.19. Anyway, Acked-by: Lukas Wunner <lukas@xxxxxxxxx> and thanks a lot for looking into it. Please cc dri-devel for vga_switcheroo-related patches in the future (now added, + Alex, links for context: https://patchwork.kernel.org/patch/10598735/ https://bugzilla.kernel.org/show_bug.cgi?id=200945 ). Lukas _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
