Re: [gentoo-user] Do I need firmware for an integrated graphics unit?

[Alan Mackenzie <acm@muc.de>]

Hello, Michael.

On Wed, Aug 21, 2024 at 12:37:53 +0100, Michael wrote:
> On Wednesday, 21 August 2024 12:15:22 BST Alan Mackenzie wrote:
> > Hello, Peter.

> > On Tue, Aug 20, 2024 at 23:16:39 +0200, Peter Böhm wrote:
> > > Hello Alan,

> > > > Anyhow, I'm up to the stage of configuring the kernel, and I'm stuck at
> > > > the bit where I need to specify the firmware to be incorporated into the
> > > > kernel for the integrated graphics processor.

> > > Yes, you surely will need some firmware files for your GPU of your AMD
> > > CPU. The easiest way to find out what you need is:

> > > Boot with our GentooLiveCD (*) and ask:

> > > "dmesg | grep firmware"

> > I've done that, and see just three firmware files:

> > regulatory.db
> > regulatory.db.p7s
> > rtl_nic/rtl8125b-2.fw

> > ..  The first, according to file, is a wireless regulatory database file.
> > The second is some variant of this, I think a signed version or
> > something.  The third is surely firmware for my Realtek 8125 Ethernet
> > chip.

> > That's not yet got me very far.

> You'll need the above if you using WiFi, but for your graphics can you please 
> take a look/share the output of:

> lspci | grep -i VGA

I've tried that already.  I get

    VGA compatible controller, Advanced Micro Devices, Inc [AMD/ATI] Raphael (rev c4)

, which fails to identify the GPU cores.  Raphael, I believe, is just the
code name for the entire processor.

> and

> lshw -C cpu

> lshw -C display

They don't give me any more information, either.

> The above will show which APU you are using and its GPU cores.  Then it is a 
> matter of looking here for the corresponding GPU chipset and microarchitecture 
> you need to enable in the kernel:

> https://wiki.gentoo.org/wiki/AMDGPU#Feature_support

I've tried that already.  "Raphael" does not appear in that document.

> before you check what firmware blobs you also need to include, from this 
> table:

> https://wiki.gentoo.org/wiki/AMDGPU#Firmware_blobs_for_a_known_card_model

That is my problem - discovering the "known card model" for my Ryzen
7900.  The Gentoo documentation doesn't appear to deal with this case,
and my three hour web search yesterday turned up nothing useful.

> Alternatively, as Wol mentioned, you can set up your kernel graphics drivers 
> as modules (temporarily) and inspect dmesg to find out what firmware is being 
> loaded.  Then use this information to add the firmware file names to be built 
> in the kernel and also configure to be built-in any kernel graphics drivers.

That would involve me learning how to make and handle a modular kernel,
something I'd really rather not have to do.  Why is the identity of the
necessary firmware for Ryzen APUs such a closely guarded secret?

-- 
Alan Mackenzie (Nuremberg, Germany).