+Ludovic On 8 March 2016 at 22:54, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > On 4 March 2016 at 14:48, Ludovic Desroches <ludovic.desroches@xxxxxxxxx> wrote: >> Hi Ulf, >> >> On Fri, Mar 04, 2016 at 10:09:37AM +0100, Ulf Hansson wrote: >>> On 17 February 2016 at 11:35, Ludovic Desroches >> >> [snip] >> >>> > I am wondering if I should take account of sdio irq enabled or not here. >>> > >>> > I have a sdio device which drives me crazy because of power management. >>> > The driver of this device is in staging, it is wilc1000. It seems that I >>> > am stuck because the sdio irq are not received. If I don't disable the >>> > clock of the controller (hclock), I should receive the sdio IRQ as I >>> > receive card detect ones, isn't it? >>> > >>> > It doesn't work, it seems I have also to not disabled mainck and gck >>> > which are clocks needed to generate the clock sent to the sdio device. >>> > If none of the clocks have to be disabled, where it has to be managed? >>> >>> That's a typical issue for SDIO IRQs, especially when the controller >>> HW manages IRQs (there are other ways to deal with SDIO IRQs as well). >>> >>> Currently, the simplest way to deal with this in the driver is to do a >>> pm_runtime_get_sync() when the SDIO IRQ gets enabled, and >>> pm_runtime_put() when it gets disabled. >> >> Which driver? sdio device driver or controller driver? > > In the mmc controller driver. > >> >>> > >>> > Do I have to anticipate this use case in the driver of my sdhci >>> > controller or does it have to be managed in the sdio device driver? They >>> > are using sdio_claim/release_host to suspend or resume the host but >>> > maybe they use it in a bad way. >>> >>> The wilc100 SDIO func driver should *not* keep the host claimed to >>> deal with SDIO irqs. Only when it configures them. >>> >>> Instead, you need to deal with this in the sdhci driver, when you get >>> the call to enable/disable SDIO IRQs. >>> >> >> Do you mean in sdhci_enable_sdio_irq? > > I am not sure exactly where to check. As it may be depending on the > sdhci variant and the SoC you probably need to deal with this in > non-common sdhci code. > >> >>> Moreover, from a system PM point of view. If the wilc100 SDIO func >>> driver wants the platform to wake up on SDIO IRQs, it needs to set >>> MMC_PM_KEEP_POWER and MMC_PM_WAKE_SDIO_IRQ from its ->suspend() >>> callback. >>> >>> In that way, your sdhci driver can act accordingly from its system PM >>> callbacks. In other words, depending on MMC_PM_KEEP_POWER and >>> MMC_PM_WAKE_SDIO_IRQ to *not* call pm_runtime_force_suspend(). >>> >> >> Ok, it makes sense. >> >> >> Coming back to the initial discussion and patch which were motivated by >> the fact that after runtime suspend I can't wake-up on card detect event, >> I have the feeling we don't have the same assumption about runtime PM. >> >> From what you and Adrian told me, I should not use runtime PM if I have >> no way to wake-up. In your minds, the way to wake-up is to use an >> externel GPIO because the controller will be 'totally' disabled, isn't it? > > I agree to the first part here. > > Although, as you also have the option to use polling for card detect, > this actually means you don't really *need* to have a wakeup > configured. Especially in the case where you don't have GPIO card > detect. > > In that way, *all* the clocks can gated in between the polling > attempts, thus you will save power even in the polling mode > configuration and when runtime PM is enabled. > >> >> On my side, runtime PM allows me to save power when the sdhci controller >> is not used. If I can disable two clocks out of three, I should use >> runtime PM. Do you agree? >> >> If not, tell me how I can convince you :) Otherwise, next step is to rework >> my patch but I think I have no other solution that not calling >> sdhci_runtime_suspend_host if I expect to use the card detect irq of the >> controller. > > So, to summarize. > > I think the best fix is to add a clever check in ->probe() and then > enable polling when you can't rely on GPIO card detect IRQ. > > Moreover, to have a robust solution, you also need to clear > SDHCI_QUIRK_BROKEN_CARD_DETECTION for your sdhci variant, as otherwise > the "broken-cd" DT binding could wrongly be used for this variant. > > Does that make sense? > > Kind regards > Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
