On Fri, 2026-05-29 at 18:46 +0300, Govindapillai, Vinod wrote:
> On Fri, 2026-05-29 at 18:20 +0300, Ville Syrjälä wrote:
> > On Fri, May 29, 2026 at 04:39:13PM +0300, Jani Nikula wrote:
> > > On Thu, 28 May 2026, Vinod Govindapillai
> > > <[email protected]> wrote:
> > > > Pcode reports the number of subchannels for LPDDR4 and LPDDR5.
> > > > But the page mask selection table is based on the channels. So
> > > > adjust the number of channels for LPDDR4 and LPDDR5 so that the
> > > > correct page mask can be picked. There are two subchannels per
> > > > channel.
> > > 
> > > IMO the parsing of the information belongs in intel_dram.c. If
> > > you
> > > get
> > > subchannels from pcode or where ever, intel_dram.c should figure
> > > it
> > > out,
> > > and store the number of channels in ->num_channels.
> > 
> > We actually want subchannels for QGV stuff. And that's what modern
> > pcode gives us, older pcode gave us channels instead and we convert
> > that to subchannels in the QGV code on those platforms. I have a
> > patch
> > to move the adjustment into intel_dram.c for those platforms so
> > that
> > we get consistent data out of intel_dram.c everywhere.
> > 
> > For this thing here I think the best thing would be to change the
> > table to use subchannels instead. Looks like Vinod didn't file the
> > Bspec
> > issue asking for the table to be updated there, so I just did that.
> 
> Oh.. sorry..  I suggested a wrong code yesterday on jira to be tried
> by
> the customer. So wanted to fix that! Will use the updated table when
> it
> is updated.
> 
> BR
> Vinod

Hi Ville,

Can we go ahead with updating the table in the driver to change
LPDDR4/5 to use sub channels? Or do we need to wait for the issue that
you raised need to be resolved first?

BR
Vinod

> 
> > 
> 

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