On 12/7/2022 9:30 PM, Ulf Hansson wrote: > On Thu, 1 Dec 2022 at 23:57, Bjorn Andersson <andersson@xxxxxxxxxx> wrote: >> On Wed, Oct 05, 2022 at 02:36:58PM +0530, Akhil P Oommen wrote: >> @Ulf, Akhil has a power-domain for a piece of hardware which may be >> voted active by multiple different subsystems (co-processors/execution >> contexts) in the system. >> >> As such, during the powering down sequence we don't wait for the >> power-domain to turn off. But in the event of an error, the recovery >> mechanism relies on waiting for the hardware to settle in a powered off >> state. >> >> The proposal here is to use the reset framework to wait for this state >> to be reached, before continuing with the recovery mechanism in the >> client driver. > I tried to review the series (see my other replies), but I am not sure > I fully understand the consumer part. > > More exactly, when and who is going to pull the reset and at what point? Explained in the other patch. -Akhil. > >> Given our other discussions on quirky behavior, do you have any >> input/suggestions on this? >> >>> Some clients like adreno gpu driver would like to ensure that its gdsc >>> is collapsed at hardware during a gpu reset sequence. This is because it >>> has a votable gdsc which could be ON due to a vote from another subsystem >>> like tz, hyp etc or due to an internal hardware signal. To allow >>> this, gpucc driver can expose an interface to the client driver using >>> reset framework. Using this the client driver can trigger a polling within >>> the gdsc driver. >> @Akhil, this description is fairly generic. As we've reached the state >> where the hardware has settled and we return to the client, what >> prevents it from being powered up again? >> >> Or is it simply a question of it hitting the powered-off state, not >> necessarily staying there? > Okay, so it's indeed the GPU driver that is going to assert/de-assert > the reset at some point. Right? > > That seems like a reasonable approach to me, even if it's a bit > unclear under what conditions that could happen. > > [...] > > Kind regards > Uffe
