On Thu, Jul 12, 2018 at 2:41 PM, Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx> wrote: > Hi Rafael, > > > On Wed, Jul 11, 2018 at 4:06 PM, Vivek Gautam > <vivek.gautam@xxxxxxxxxxxxxx> wrote: >> Hi Rafael, >> >> >> >> On 7/11/2018 3:23 PM, Rafael J. Wysocki wrote: >>> >>> On Sunday, July 8, 2018 7:34:12 PM CEST Vivek Gautam wrote: >>>> >>>> From: Sricharan R <sricharan@xxxxxxxxxxxxxx> >>>> >>>> Finally add the device link between the master device and >>>> smmu, so that the smmu gets runtime enabled/disabled only when the >>>> master needs it. This is done from add_device callback which gets >>>> called once when the master is added to the smmu. >>>> >>>> Signed-off-by: Sricharan R <sricharan@xxxxxxxxxxxxxx> >>>> Signed-off-by: Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx> >>>> Reviewed-by: Tomasz Figa <tfiga@xxxxxxxxxxxx> >>>> Cc: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> >>>> Cc: Lukas Wunner <lukas@xxxxxxxxx> >>>> --- >>>> >>>> - Change since v11 >>>> * Replaced DL_FLAG_AUTOREMOVE flag with DL_FLAG_AUTOREMOVE_SUPPLIER. >>>> >>>> drivers/iommu/arm-smmu.c | 12 ++++++++++++ >>>> 1 file changed, 12 insertions(+) >>>> >>>> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c >>>> index 09265e206e2d..916cde4954d2 100644 >>>> --- a/drivers/iommu/arm-smmu.c >>>> +++ b/drivers/iommu/arm-smmu.c >>>> @@ -1461,8 +1461,20 @@ static int arm_smmu_add_device(struct device *dev) >>>> iommu_device_link(&smmu->iommu, dev); >>>> + if (pm_runtime_enabled(smmu->dev) && >>> >>> Why does the creation of the link depend on whether or not runtime PM >>> is enabled for the MMU device? >> >> >> The main purpose of this device link is to handle the runtime PM >> synchronization >> between the supplier (iommu) and consumer (client devices, such as >> GPU/display). >> Moreover, the runtime pm is conditionally enabled for smmu devices that >> support >> such [1]. > > Is there something you would like me to modify in this patch? Not really, as long as you are sure that it is correct. :-) You need to remember, however, that if you add system-wide PM callbacks to the driver, the ordering between them and the client device callbacks during system-wide suspend matters as well. Don't you need the link the ensure the correct system-wide suspend ordering too? -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
