[PATCH v4 0/3] BMG PCIe Gen5 downgrade attributes and usage

[Rodrigo Vivi]

On Mon, Apr 28, 2025 at 04:00:44PM -0400, Rodrigo Vivi wrote:
> On Mon, Apr 28, 2025 at 01:12:38PM +0300, Raag Jadav wrote:
> > On Fri, Apr 25, 2025 at 07:36:23PM +0530, Raag Jadav wrote:
> > > This series exposes sysfs attributes for BMG PCIe Gen5 downgrade and
> > > documents their usage.
> > 
> > Anything I can do to move this forward?
> 
> I almost push it here, but then I noticed that it is gen5_downgrade.
> Hadn't we agreed to follow what spec says so?
> 
> "to then automatically persist the Gen4 downgrade flag in Flash"
> "Write Gen4 Downgrade bit to MRC Flash File"
> 
> == Applying  PCIe Gen4 Downgrade ==
> 
> Although I see that there are some mentions calling "Gen5 downgrade", "Gen4 downgrade" seems to be the most used term in the specs, specially when calling bits and
> sections names...

Because of the inconsistencies and our back and forth here and to get prepared
for future cases where we might need to downgrade from gen6 to gen5, the current
Architecture recommendation is to simply go with

so /sys/bus/pci/devices/<bdf>/pcie_gen_downgrade_{status,capable}

The specs are going to be updated to reflect that.

Thanks,
Rodrigo.

> 
> 
> > 
> > Raag
> > 
> > > v1: https://patchwork.freedesktop.org/series/147023/
> > > 
> > > v2: Move from debugfs to sysfs (Lucas, Rodrigo, Badal)
> > >     Rework macros and their naming (Rodrigo)
> > > 
> > > v3: Move xe_device_sysfs_init() to xe_device_probe() (Riana)
> > >     Use sysfs_create_files() (Riana)
> > >     Fix checkpatch warning (Riana)
> > > 
> > > v4: s/gen4_downspeed/gen5_downgrade (Lucas, Rodrigo, Riana)
> > > 
> > > Raag Jadav (3):
> > >   drm/xe/pm: s/xe_device_sysfs_init/xe_pm_sysfs_init
> > >   drm/xe: Expose PCIe Gen5 downgrade attributes
> > >   drm/xe/doc: Wire up PCIe Gen5 limitations
> > > 
> > >  Documentation/gpu/xe/xe_firmware.rst |   6 ++
> > >  drivers/gpu/drm/xe/xe_device.c       |   5 ++
> > >  drivers/gpu/drm/xe/xe_device_sysfs.c | 107 ++++++++++++++++++++++++++-
> > >  drivers/gpu/drm/xe/xe_device_sysfs.h |   1 +
> > >  drivers/gpu/drm/xe/xe_pcode_api.h    |   5 ++
> > >  drivers/gpu/drm/xe/xe_pm.c           |   2 +-
> > >  6 files changed, 123 insertions(+), 3 deletions(-)
> > > 
> > > -- 
> > > 2.34.1
> > >