On 30/03/2023 17:34, Konrad Dybcio wrote:
On 29.03.2023 21:45, Dmitry Baryshkov wrote:
On Wed, 29 Mar 2023 at 18:48, Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> wrote:
On 29.03.2023 16:37, Johan Hovold wrote:
On Wed, Mar 29, 2023 at 04:04:44PM +0200, Konrad Dybcio wrote:
If we fail to initialize the GPU for whatever reason (say we don't
embed the GPU firmware files in the initrd), the error path involves
pm_runtime_put_sync() which then calls idle() instead of suspend().
This is suboptimal, as it means that we're not going through the
clean shutdown sequence. With at least A619_holi, this makes the GPU
not wake up until it goes through at least one more start-fail-stop
cycle. Fix that by using pm_runtime_put_sync_suspend to force a clean
shutdown.
This does not sound right. If pm_runtime_put_sync() fails to suspend the
device when the usage count drops to zero, then you have a bug somewhere
else.
I was surprised to see that it was not called as well, but I wasn't able
to track it down before..
Could you please check that it's autosuspend who kicks in? In other
words, if we disable autosuspend, the pm_runtime_put_sync is enough()?
That would probably mean that we lack some kind of reset in the hw_init path.
On the other hand, I do not know how the device will react to the
error-in-the-middle state. Modems for example, can enter the state
where you can not properly turn it off once it starts the boot
process.
And if we remember the efforts that Akhil has put into making sure
that the GPU is properly reset in case of an _error_, it might be
nearly impossible to shut it down in a proper way.
Thus said, I think that unless there is an obvious way to restart the
init process, Korad's pm_runtime_put_sync_suspend() looks like a
correct fix to me.
On the GPU side, when you cut GX and CX GDSCs, the hardware is off.
Some clock / gdsc logic may be retained, but the GPU itself gets
cut off. Parking the clocks and shuttting down VDD_GX (if exists)
only makes that stronger.
If I remember correctly, GX and CX GPU GDSCs might be voted by other
users. Again, I'd direct you here to the series at [1]
[1]: https://patchwork.freedesktop.org/series/111966/
--
With best wishes
Dmitry
