On Monday, June 27, 2016 11:27:42 AM Hoan Tran wrote: > Hi Jassi and Rafael, > > On Wed, Jun 15, 2016 at 9:19 AM, Prakash, Prashanth > <pprakash@xxxxxxxxxxxxxx> wrote: > > > > > > On 6/9/2016 4:43 PM, Hoan Tran wrote: > >> Hi Prashanth, > >> > >> On Thu, Jun 9, 2016 at 3:25 PM, Prakash, Prashanth > >> <pprakash@xxxxxxxxxxxxxx> wrote: > >>> > >>> On 6/9/2016 2:47 PM, Hoan Tran wrote: > >>>> Hi Ashwin and Prashanth, > >>>> > >>>> On Wed, Jun 8, 2016 at 5:41 PM, Hoan Tran <hotran@xxxxxxx> wrote: > >>>>> Hi Prashanth, > >>>>> > >>>>> > >>>>> On Wed, Jun 8, 2016 at 5:32 PM, Prakash, Prashanth > >>>>> <pprakash@xxxxxxxxxxxxxx> wrote: > >>>>>> On 6/8/2016 10:24 AM, Hoan Tran wrote: > >>>>>>> Hi Ashwin, > >>>>>>> > >>>>>>> On Wed, Jun 8, 2016 at 5:18 AM, Ashwin Chaugule > >>>>>>> <ashwin.chaugule@xxxxxxxxxx> wrote: > >>>>>>>> + Prashanth (Can you please have a look as well?) > >>>>>>>> > >>>>>>>> On 31 May 2016 at 15:35, Hoan Tran <hotran@xxxxxxx> wrote: > >>>>>>>>> Hi Ashwin, > >>>>>>>> Hi, > >>>>>>>> > >>>>>>>> Sorry about the delay. I'm in the middle of switching jobs and > >>>>>>>> locations, so its been a bit crazy lately. > >>>>>>> It's ok and hope you're doing well. > >>>>>>> > >>>>>>>> I dont have any major > >>>>>>>> concerns with this code, although there could be subtle issues with > >>>>>>>> this IRQ thing. In this patchset, your intent is to add support for > >>>>>>>> PCC subspace type 2. But you're also adding support for tx command > >>>>>>>> completion which is not specific to Type 2. We could support that even > >>>>>>>> in Type 1. Hence I wanted to separate the two, not just for review, > >>>>>>>> but also the async IRQ completion has subtle issues esp. in the case > >>>>>>>> of async platform notification, where you could have a PCC client in > >>>>>>>> the OS writing to the cmd bit and the platform sending an async > >>>>>>>> notification by writing to some bits in the same 8byte address as the > >>>>>>>> cmd bit. So we need some mutual exclusivity there, otherwise the OS > >>>>>>>> and platform could step on each other. Perhaps Prashanth has better > >>>>>>>> insight into this. > >>>>>>> I think, this mutual exclusivity could be in another patch. > >>>>>> Ashwin, > >>>>>> Sorry, I am not sure how we can prevent platform and OSPM from stepping on > >>>>>> each other. There is a line is spec that says "all operations on status field > >>>>>> must be made using interlocked operations", but not sure what these > >>>>>> interlocked operation translates to. > >>>>> Yes, I had the same question about how to prevent it. > >>>> For platform notification, if the hardware doesn't support interlocked > >>>> operations. I think we can use a workaround that, platform triggers > >>>> interrupt to OSPM without touching status field. The OSPM PCC client > >>>> will decide what to do with this interrupt. For example, OSPM sends a > >>>> consumer command to check it. > >>> How do we decide which platform can support this interlocked operation? > >>> and how do we decide between a completion notification and platform > >>> notification? > >> Truly, we should follow the specification. But I don't know if there's > >> any hardware support this interlocked operation. > >> For the decide between a completion notification and platform notification > >> - Completion notification: Bit "Command Complete" is set. > >> - Platform notification: Bit "Command Complete" is not set. > >> > >>> I think the ACPI spec on platform notification is quite ambiguous and it is > >>> best to get the necessary clarification and/or correction before implementing > >>> anything related to platform notification. > >> Agreed, a clarification inside ACPI Specification is needed > > This patch look good to me, as it doesn't deal with platform notification. > > We can try to get some clarification from spec side before handling the platform > > notification pieces. > > > > Reviewed-by: Prashanth Prakash <pprakash@xxxxxxxxxxxxxx> > > Do you have plan to apply this patch ? Yes. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
