On 5/14/2018 12:01 PM, Ayan Halder wrote:
On Wed, Apr 25, 2018 at 01:49:35PM +0200, Daniel Vetter wrote:
Hi Daniel,
On Wed, Apr 25, 2018 at 1:26 PM, Liviu Dudau <liviu.dudau@xxxxxxx> wrote:
On Wed, Apr 25, 2018 at 09:17:22AM +0200, Daniel Vetter wrote:
On Tue, Apr 24, 2018 at 07:12:47PM +0100, Ayan Kumar Halder wrote:
malidp_pm_suspend_late checks if the runtime status is not suspended
and if so, invokes malidp_runtime_pm_suspend which disables the
display engine/core interrupts and the clocks. It sets the runtime status
as suspended.
The difference between suspend() and suspend_late() is as follows:-
1. suspend() makes the device quiescent. In our case, we invoke the DRM
helper which disables the CRTC. This would have invoked runtime pm
suspend but the system suspend process disables runtime pm.
2. suspend_late() It continues the suspend operations of the drm device
which was started by suspend(). In our case, it performs the same functionality
as runtime_suspend().
The complimentary functions are resume() and resume_early(). In the case of
resume_early(), we invoke malidp_runtime_pm_resume() which enables the clocks
and the interrupts. It sets the runtime status as active. If the device was
in runtime suspend mode before system suspend was called, pm_runtime_work()
will put the device back in runtime suspended mode( after the complete system
has been resumed).
Signed-off-by: Ayan Kumar Halder <ayan.halder@xxxxxxx>
Afaiui we still haven't bottomed out on the discussion on v1. Did you get
hold of Rafael?
No, there was no reply from him. Lets try again:
Rafael, we are debating on what the proper approach is for handling the
suspend/resume callbacks for a DRM driver that is likely to not be
runtime suspended when the power-down happens (because we are driving
the display output). We are using in this patch the LATE_SYSTEM_SLEEP_PM_OPS
in order to do the work that we also do during runtime suspend, which is
turning off the output and the clocks driving it. The reason for doing
that is because the PM core takes a runtime reference during system
suspend for all devices that are not already runtime suspended, so our
runtime_pm_suspend() hook is never called.
Daniel's argument is that we should not be doing this from LATE hooks,
but from the normal suspend hooks, however kernel doc seems to suggest
otherwise.
For more context: I thought the reason behind the recommendation to
stuff the rpm callbacks into the late/early hooks was to solve
cross-device ordering issues. That way everyone shuts down the device
functionality in the normal hooks, but only powers them off in the
late hook (to allow other drivers to keep using the clock/i2c
master/whatever). But we now have device_link to solve that since a
while, so I'm not sure the recommendation to stuff the rpm hooks into
late/early callbacks is still correct.
-Daniel
It has been more than two weeks and we have not got any response from
Rafael. Can you ping him personally or suggest any way by which ask
him to respond?
It is in my queue though, sorry for the delay.
It would help if you resent the series with a CC to
linux-pm@xxxxxxxxxxxxxxx as it would be easier for me to review it then.
Thanks,
Rafael
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
