On Fri, May 14, 2021 at 05:53:18PM +0200, Ulrich Hecht wrote: > The TMIO core sets a very low latency limit (100 us), but when using R-Car > SDHI hosts with SD cards, I have observed typical latencies of around 20-30 > ms. This prevents runtime PM from working properly, and the devices remain > on continuously. > > This patch sets the default latency limit to 100 ms to avoid that. > > Signed-off-by: Ulrich Hecht <uli+renesas@xxxxxxxx> Adding Shimoda-san to CC. Shimoda-san: can you kindly run your SDHI tests with this patch applied? That would be very kind, thank you! > --- > drivers/mmc/host/renesas_sdhi_core.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c > index 635bf31a6735..4f41616cc6bb 100644 > --- a/drivers/mmc/host/renesas_sdhi_core.c > +++ b/drivers/mmc/host/renesas_sdhi_core.c > @@ -32,6 +32,7 @@ > #include <linux/pinctrl/pinctrl-state.h> > #include <linux/platform_device.h> > #include <linux/pm_domain.h> > +#include <linux/pm_qos.h> > #include <linux/regulator/consumer.h> > #include <linux/reset.h> > #include <linux/sh_dma.h> > @@ -1147,6 +1148,9 @@ int renesas_sdhi_probe(struct platform_device *pdev, > host->ops.hs400_complete = renesas_sdhi_hs400_complete; > } > > + /* keep tmio_mmc_host_probe() from setting latency limit too low */ > + dev_pm_qos_expose_latency_limit(&pdev->dev, 100000); > + > ret = tmio_mmc_host_probe(host); > if (ret < 0) > goto edisclk; > -- > 2.20.1 >
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