Re: [PATCH v4] platform/x86/amd/pmc: adjust getting DRAM size behavior

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

On Thu, 16 Nov 2023, Mario Limonciello wrote:

> On 11/16/2023 11:01, Shyam Sundar S K wrote:
> > amd_pmc_get_dram_size() is used to get the DRAM size information. But in
> > the current code, mailbox command to get the DRAM size info is sent based
> > on the values of dev->major and dev->minor.
> > 
> > But dev->major and dev->minor will have either junk or zero assigned to
> > them until at least once a call to amd_pmc_get_smu_version() is made which
> > ideally populates dev->major and dev->minor.
> > 
> > Ideally to suffice this, adding a amd_pmc_get_smu_version() call to
> > amd_pmc_get_dram_size() would solve, but that has a downside of elevating
> > the boot times.
> > 
> > After talking to the PMFW team, its understood that the "get dram size"
> > mbox command would only be supported on specific platforms (like Mendocino)
> > and not all. So, adjust getting DRAM size behavior such that,
> > 
> > - if that's Rembrandt or Mendocino and the underlying PMFW knows how
> > to execute the "get dram size" command it shall give the custom dram size.
> > 
> > - if the underlying FW does not report the dram size, we just proceed
> > further and assign the default dram size.
> > 
> > Simplest way to address this is to remove amd_pmc_get_dram_size() function
> > and directly call the "get dram size" command in the amd_pmc_s2d_init().
> > 
> > Reported-by: Mark Hasemeyer <markhas@chromium.org>
> > Closes:
> > https://lore.kernel.org/platform-driver-x86/3b224c62-a1d8-41bd-aced-5825f5f20e66@amd.com/
> > Fixes: be8325fb3d8c ("platform/x86/amd: pmc: Get STB DRAM size from PMFW")
> > Suggested-by: Sanket Goswami <Sanket.Goswami@amd.com>
> > Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
> 
> Ilpo when committing can you please add a stable tag for this?
>
> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>

I'll add it, thanks.

-- 
 i.