On 24/01/2020 09:07, Jon Hunter wrote: > > On 23/01/2020 15:16, Dmitry Osipenko wrote: >> 23.01.2020 12:22, Sameer Pujar пишет: >>> >>> >>> On 1/22/2020 9:57 PM, Dmitry Osipenko wrote: >>>> External email: Use caution opening links or attachments >>>> >>>> >>>> 22.01.2020 14:52, Jon Hunter пишет: >>>>> On 22/01/2020 07:16, Sameer Pujar wrote: >>>>> >>>>> ... >>>>> >>>>>>>>>>>> +static int tegra210_i2s_remove(struct platform_device *pdev) >>>>>>>>>>>> +{ >>>>>>>>>>>> + pm_runtime_disable(&pdev->dev); >>>>>>>>>>>> + if (!pm_runtime_status_suspended(&pdev->dev)) >>>>>>>>>>>> + tegra210_i2s_runtime_suspend(&pdev->dev); >>>>>>>>>>> This breaks device's RPM refcounting if it was disabled in the >>>>>>>>>>> active >>>>>>>>>>> state. This code should be removed. At most you could warn >>>>>>>>>>> about the >>>>>>>>>>> unxpected RPM state here, but it shouldn't be necessary. >>>>>>>>>> I guess this was added for safety and explicit suspend keeps clock >>>>>>>>>> disabled. >>>>>>>>>> Not sure if ref-counting of the device matters when runtime PM is >>>>>>>>>> disabled and device is removed. >>>>>>>>>> I see few drivers using this way. >>>>>>>>> It should matter (if I'm not missing something) because RPM should >>>>>>>>> be in >>>>>>>>> a wrecked state once you'll try to re-load the driver's module. >>>>>>>>> Likely >>>>>>>>> that those few other drivers are wrong. >>>>>>>>> >>>>>>>>> [snip] >>>>>>>> Once the driver is re-loaded and RPM is enabled, I don't think it >>>>>>>> would use >>>>>>>> the same 'dev' and the corresponding ref count. Doesn't it use the >>>>>>>> new >>>>>>>> counters? >>>>>>>> If RPM is not working for some reason, most likely it would be the >>>>>>>> case >>>>>>>> for other >>>>>>>> devices. What best driver can do is probably do a force suspend >>>>>>>> during >>>>>>>> removal if >>>>>>>> already not done. I would prefer to keep, since multiple drivers >>>>>>>> still >>>>>>>> have it, >>>>>>>> unless there is a real harm in doing so. >>>>>>> I took a closer look and looks like the counter actually should be >>>>>>> reset. Still I don't think that it's a good practice to make changes >>>>>>> underneath of RPM, it may strike back. >>>>>> If RPM is broken, it probably would have been caught during device >>>>>> usage. >>>>>> I will remove explicit suspend here if no any concerns from other >>>>>> folks. >>>>>> Thanks. >>>>> I recall that this was the preferred way of doing this from the RPM >>>>> folks. Tegra30 I2S driver does the same and Stephen had pointed me to >>>>> this as a reference. >>>>> I believe that this is meant to ensure that the >>>>> device is always powered-off regardless of it RPM is enabled or not and >>>>> what the current state is. >>>> Yes, it was kinda actual for the case of unavailable RPM. >>> >>>> Anyways, /I think/ variant like this should have been more preferred: >>>> >>>> if (!pm_runtime_enabled(&pdev->dev)) >>>> tegra210_i2s_runtime_suspend(&pdev->dev); >>>> else >>>> pm_runtime_disable(&pdev->dev); >>> >>> I think it looks to be similar to what is there already. >>> >>> pm_runtime_disable(&pdev->dev); // it would turn out to be a dummy call >>> if !RPM >>> if (!pm_runtime_status_suspended(&pdev->dev)) // it is true always if !RPM >>> tegra210_i2s_runtime_suspend(&pdev->dev); >> >> Maybe this is fine for !RPM, but not really fine in a case of enabled >> RPM. Device could be in resumed state after pm_runtime_disable() if it >> wasn't suspended before the disabling. > > I don't see any problem with this for the !RPM case. Sorry I meant the RPM case. In other words, I don't see a problem for neither the RPM case of the !RPM case. Jon -- nvpublic _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel