Messages in this thread | | | Subject | Re: [PATCH v12 3/4] iommu/arm-smmu: Add the device_link between masters and smmu | From | Vivek Gautam <> | Date | Mon, 16 Jul 2018 17:16:31 +0530 |
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On 7/16/2018 2:25 PM, Rafael J. Wysocki wrote: > On Thu, Jul 12, 2018 at 2:41 PM, Vivek Gautam > <vivek.gautam@codeaurora.org> wrote: >> Hi Rafael, >> >> >> On Wed, Jul 11, 2018 at 4:06 PM, Vivek Gautam >> <vivek.gautam@codeaurora.org> 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@codeaurora.org> >>>>> >>>>> 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@codeaurora.org> >>>>> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org> >>>>> Reviewed-by: Tomasz Figa <tfiga@chromium.org> >>>>> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> >>>>> Cc: Lukas Wunner <lukas@wunner.de> >>>>> --- >>>>> >>>>> - 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?
The fact that currently we handle clocks only through runtime pm callbacks, would it be better to call runtime pm put/get in system-wide PM callbacks. This would be same as i mentioned in the other thread.
Best regards Vivek
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