VT console blank ignored by DRM drivers on QEMU

[Takashi Iwai]

On Tue, 11 Jul 2017 19:35:36 +0200,
Daniel Vetter wrote:
> 
> On Mon, Jul 10, 2017 at 4:56 PM, Daniel Vetter <daniel at ffwll.ch> wrote:
> > On Mon, Jul 10, 2017 at 11:37 AM, Takashi Iwai <tiwai at suse.de> wrote:
> >>> DPMS should be an error anyway, we want that to be able to properly
> >>> thread the acquire_ctx EDEADLK backoff stuff through that we need for
> >>> atomic. That would be the best long-term plan I think.
> >>
> >> So it implies the conversions of the whole legacy stuff?
> >> That'd be great but take a long way :)
> >>
> >>> But aside from that, can't we just teach these drivers to properly do
> >>> dpms? With the atomic framework dpms is implement as simply turning
> >>> the screen off, any driver should be able to support that properly.
> >>
> >> It seems that QEMU doesn't support it yet?  We'd need to implement it
> >> at first there.
> >
> > I meant to say that adding an error code to the dpms callback seems
> > like a good idea, because we need that anyway. You can ignore the
> > blabla about why exactly atomic drivers need it, and ofc I'm not going
> > to suggest that you convert all your drivers over to atomic first.
> 
> I just realized that we've switched the dpms callback from void to int
> return type a while ago. So only thing you'd need to do is wire up the
> return code through the fbdev helpers, and fix up the virtual drivers
> to not allow dpms.

Hmm, as of 4.13-rc1, I see some inconsistencies:

In drm_connector.h:
struct drm_connector_funcs {
	int (*dpms)(struct drm_connector *connector, int mode);

In drm_encoder_slave.h:
struct drm_encoder_slave_funcs {
	void (*dpms)(struct drm_encoder *encoder, int mode);

In drm_modeset_helper_vtables.h:
struct drm_crtc_helper_funcs {
	void (*dpms)(struct drm_crtc *crtc, int mode);

struct drm_encoder_helper_funcs {
	void (*dpms)(struct drm_encoder *encoder, int mode);


Takashi