RE: [PATCH V4 2/2] PCI: rcar: Recalculate inbound range alignment for each controller entry

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Lorenzo,

> From: Lorenzo Pieralisi, Sent: Tuesday, October 29, 2019 7:35 PM
> 
> On Tue, Oct 29, 2019 at 01:18:04AM +0000, Yoshihiro Shimoda wrote:
> > Hi Lorenzo,
> >
> > > From: Lorenzo Pieralisi, Sent: Monday, October 28, 2019 7:21 PM
> > >
> > > On Mon, Oct 28, 2019 at 08:35:32AM +0000, Yoshihiro Shimoda wrote:
> > > > Hi Marek-san.
> > > >
> > > > > From: Marek Vasut, Sent: Sunday, October 27, 2019 3:27 AM
> > > > >
> > > > > Due to hardware constraints, the size of each inbound range entry
> > > > > populated into the controller cannot be larger than the alignment
> > > > > of the entry's start address. Currently, the alignment for each
> > > > > "dma-ranges" inbound range is calculated only once for each range
> > > > > and the increment for programming the controller is also derived
> > > > > from it only once. Thus, a "dma-ranges" entry describing a memory
> > > > > at 0x48000000 and size 0x38000000 would lead to multiple controller
> > > > > entries, each 0x08000000 long.
> > > >
> > > > I added a debug code [1] and I confirmed that each entry is not 0x08000000 long [2].
> > > >
> > > > After fixed the commit log above,
> > >
> > > So what does this mean in practice ? Does it mean that the commit log is
> > > wrong or that the issue is not present as described, in the mainline
> > > code ?
> >
> > I meant the commit log is wrong. In such the case, the multiple controller
> > entries has 3 kind of size like below.
> 
> OK, that's confusing. The commit log is describing the issue it is
> fixing and you are reporting that's not what happens in practice, so in
> short my question is, is it possible to describe the issue you
> are fixing with an example representative of what's happening and
> explaining why we need to apply this patch please ?

I'm very sorry, I completely misunderstood the original commit description.
I misunderstood "each 0x08000000 log" was a behavior of after we applied
this patch...

So, the description is no problem. In other words, we don't need to fix
any description on this patch.

Best regards,
Yoshihiro Shimoda





[Index of Archives]     [DMA Engine]     [Linux Coverity]     [Linux USB]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Greybus]

  Powered by Linux