Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1391692

Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR allocation

Show all headers | View raw

(Pulling in efifb maintainer, Peter)

On Fri, 29 Apr, at 06:31:19PM, Bjorn Helgaas wrote:
> 
> The efifb.c driver doesn't do anything at all with PCI (it includes
> linux/pci.h, but probably doesn't need it).  That's part of what I'm
> suggesting -- if it *did* register as a PCI device driver, then it
> would look at pci_dev->resource[n], which is populated by the PCI
> core based on the BAR values.
 
This discussion came up recently here,

  https://lkml.kernel.org/r/20160216151859.GB11373@redhat.com

There's nothing PCI-specific about the EFI framebuffer per se, but in
practice it's always a PCI device.

> Is ConOut what you're after?  I.e., is the whole point of this
> exercise to get a framebuffer driver attached to the device that was
> the firmware console?  I would think the ConOut path should be
> decodable -- it has to tell you how to navigate the interconnect from
> the CPU to the device.  But I don't know how to do it.
> 
> It looks like on x86, at least, setup_gop32()/setup_gop64() might be
> extracting the framebuffer address from the ConOut device and stuffing
> it into screen_info, which is what efifb.c later looks at (maybe this
> is what Ard was referring to).
 
Matthew Garrett wrote the x86 code for guessing where the console is.
We look for the ConOut protocol with a fallback to first GOP device if
we can't find it. I think the heuristic was based on reading the
implementation in EDK2. See commit 38cb5ef4473c ("X86: Improve GOP
detection in the EFI boot stub").

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR  allocation Bjorn Helgaas <helgaas@kernel.org> - 2016-04-28 18:30 +0200
  Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR  allocation Alexander Graf <agraf@suse.de> - 2016-04-28 18:50 +0200
    Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR  allocation Bjorn Helgaas <helgaas@kernel.org> - 2016-04-28 20:10 +0200
      Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR  allocation Alexander Graf <agraf@suse.de> - 2016-04-28 23:40 +0200
        Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR  allocation Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2016-04-29 12:10 +0200
        Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR  allocation Bjorn Helgaas <helgaas@kernel.org> - 2016-04-29 15:50 +0200
          Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR allocation Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-04-29 16:00 +0200
            Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR  allocation Bjorn Helgaas <helgaas@kernel.org> - 2016-04-29 22:10 +0200
              Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR allocation Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-04-29 22:30 +0200
                Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR  allocation Alexander Graf <agraf@suse.de> - 2016-04-29 23:00 +0200
                Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR  allocation Bjorn Helgaas <helgaas@kernel.org> - 2016-04-29 23:40 +0200
                Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR  allocation Alexander Graf <agraf@suse.de> - 2016-04-30 00:00 +0200
                Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR  allocation Alexander Graf <agraf@suse.de> - 2016-04-30 00:10 +0200
                Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR  allocation Bjorn Helgaas <helgaas@kernel.org> - 2016-04-30 01:40 +0200
                Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR  allocation Matt Fleming <matt@codeblueprint.co.uk> - 2016-04-30 23:20 +0200
                Re: [PATCH] arm64: Relocate screen_info.lfb_base on PCI BAR  allocation Bjorn Helgaas <helgaas@kernel.org> - 2016-04-29 23:30 +0200

csiph-web