| Message ID | 20180712170256.13018-3-lyude@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Jul 12, 2018 at 01:02:53PM -0400, Lyude Paul wrote: > --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c > +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c > @@ -1878,7 +1878,7 @@ nv50_disp_atomic_commit(struct drm_device *dev, > nv50_disp_atomic_commit_tail(state); > > drm_for_each_crtc(crtc, dev) { > - if (crtc->state->enable) { > + if (crtc->state->active) { > if (!drm->have_disp_power_ref) { > drm->have_disp_power_ref = true; > return 0; Somewhat tangential comment on this older patch, since you continue to dig around in the runtime PM area: Whenever a crtc is activated or deactivated in nouveau, we iterate over all crtcs and acquire a runtime PM if a crtc is active and previously there was no active one, or we drop a ref if none is active and previously there was an active one. For a while now I've been thinking that it would be more straightforward to acquire a ref whenever a crtc is activated and drop one when a crtc is deactivated, i.e. hold one ref for every active crtc. That way the have_disp_power_ref variable as well as the iteration logic could be removed, leading to a simplification. Just a suggestion anyway. Thanks, Lukas
On Tue, Jul 17, 2018 at 09:33:52AM +0200, Lukas Wunner wrote: > On Thu, Jul 12, 2018 at 01:02:53PM -0400, Lyude Paul wrote: > > --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c > > +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c > > @@ -1878,7 +1878,7 @@ nv50_disp_atomic_commit(struct drm_device *dev, > > nv50_disp_atomic_commit_tail(state); > > > > drm_for_each_crtc(crtc, dev) { > > - if (crtc->state->enable) { > > + if (crtc->state->active) { > > if (!drm->have_disp_power_ref) { > > drm->have_disp_power_ref = true; > > return 0; > > Somewhat tangential comment on this older patch, since you > continue to dig around in the runtime PM area: > > Whenever a crtc is activated or deactivated in nouveau, we iterate > over all crtcs and acquire a runtime PM if a crtc is active and > previously there was no active one, or we drop a ref if none is > active and previously there was an active one. > > For a while now I've been thinking that it would be more straightforward > to acquire a ref whenever a crtc is activated and drop one when a crtc > is deactivated, i.e. hold one ref for every active crtc. That way the > have_disp_power_ref variable as well as the iteration logic could be > removed, leading to a simplification. Just a suggestion anyway. The current code looks somewhat busted anyway. First problem is that it's accessing crtc->state without the appropriate locks held (unless something always pulls in all crtcs to every commit?). Second issue is that the rpm_put() is called without waiting for nonblocking commits to have finished so it looks like you can currentlly remove the power before the hardware has been properly shut down.
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c index d9da69c83ae7..9bae4db84cfb 100644 --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c @@ -1878,7 +1878,7 @@ nv50_disp_atomic_commit(struct drm_device *dev, nv50_disp_atomic_commit_tail(state); drm_for_each_crtc(crtc, dev) { - if (crtc->state->enable) { + if (crtc->state->active) { if (!drm->have_disp_power_ref) { drm->have_disp_power_ref = true; return 0;
A CRTC being enabled doesn't mean it's on! It doesn't even necessarily mean it's being used. This fixes runtime PM leaks on the P50 I've got next to me. Signed-off-by: Lyude Paul <lyude@redhat.com> Cc: stable@vger.kernel.org --- drivers/gpu/drm/nouveau/dispnv50/disp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)