Re: [PATCH 2/2] efi: Add embedded peripheral firmware support

[Luis R. Rodriguez]

On Thu, Apr 05, 2018 at 07:43:49AM +0200, Lukas Wunner wrote:
> On Wed, Apr 04, 2018 at 01:18:36PM -0400, Peter Jones wrote:
> > > On Tue, Apr 03, 2018 at 08:07:11PM +0200, Lukas Wunner wrote:
> > > > * Add the EFI Firmware Volume Protocol to include/linux/efi.h:
> > > >   https://www.intel.com/content/dam/doc/reference-guide/efi-firmware-file-volume-specification.pdf
> > > > 
> > > > * Amend arch/x86/boot/compressed/eboot.c to read the files with the
> > > >   GUIDs you're interested in into memory and pass the files to the
> > > >   kernel as setup_data payloads.
> > 
> > To be honest, I'm a bit skeptical about the firmware volume approach.
> > Tools like UEFITool[0] and uefi-firmware-parser[1] have existed for
> > years, still don't seem to reliably parse firmware images I see in the
> > wild, and have a fairly regular need for fixes.  These are tools
> > maintained by smart people who are making a real effort, and it still
> > looks pretty hard to do a good job that applies across a lot of
> > platforms.
> > 
> > So I'd rather use Hans's existing patches, at least for now, and if
> > someone is interested in hacking on making an efi firmware volume parser
> > for the kernel, switch them to that when such a thing is ready.
> 
> Hello?  As I've written in the above-quoted e-mail the kernel should
> read the files using EFI_FIRMWARE_VOLUME_PROTOCOL.ReadFile().
> 
> *Not* by parsing the firmware volume!
> 
> Parsing the firmware volume is only necessary to find out the GUIDs
> of the files you're looking for.  You only do that *once*.

How do you get the GUIDs for each driver BTW?

Hans, I do believe we should *try* this approach at the very least.

Why not?

Otherwise it would be wise to provide a technical reason for why
we'd choose one custom mechanism which would only serve a few tablets
over a mechanism which could serve more devices.

  Luis