linux-kernel - Re: [PATCH v2 00/14] efi/gop: Refactoring + mode-setting feature

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Date:   Wed, 25 Mar 2020 17:41:43 +0100
From:   Ard Biesheuvel <ardb@...nel.org>
To:     Arvind Sankar <nivedita@...m.mit.edu>
Cc:     Hans de Goede <hdegoede@...hat.com>,
        linux-efi <linux-efi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 00/14] efi/gop: Refactoring + mode-setting feature

On Fri, 20 Mar 2020 at 03:00, Arvind Sankar <nivedita@...m.mit.edu> wrote:
>
> This series is against tip:efi/core.
>
> Patches 1-9 are small cleanups and refactoring of the code in
> libstub/gop.c.
>
> The rest of the patches add the ability to use a command-line option to
> switch the gop's display mode.
>
> The options supported are:
> video=efifb:mode=n
>         Choose a specific mode number
> video=efifb:<xres>x<yres>[-(rgb|bgr|<bpp>)]
>         Specify mode by resolution and optionally color depth
> video=efifb:auto
>         Let the EFI stub choose the highest resolution mode available.
>
> The mode-setting additions increase code size of gop.o by about 3k on
> x86-64 with EFI_MIXED enabled.
>
> Changes in v2 (HT lkp@...el.com):
> - Fix __efistub_global attribute to be after the variable.
>   (NB: bunch of other places should ideally be fixed, those I guess
>   don't matter as they are scalars?)
> - Silence -Wmaybe-uninitialized warning in set_mode function.
>

These look good to me. The only question I have is whether it would be
possible to use the existing next_arg() and parse_option_str()
functions to replace some of the open code parsing that goes on in
patches 11 - 14.


> Arvind Sankar (14):
>   efi/gop: Remove redundant current_fb_base
>   efi/gop: Move check for framebuffer before con_out
>   efi/gop: Get mode information outside the loop
>   efi/gop: Factor out locating the gop into a function
>   efi/gop: Slightly re-arrange logic of find_gop
>   efi/gop: Move variable declarations into loop block
>   efi/gop: Use helper macros for populating lfb_base
>   efi/gop: Use helper macros for find_bits
>   efi/gop: Remove unreachable code from setup_pixel_info
>   efi/gop: Add prototypes for query_mode and set_mode
>   efi/gop: Allow specifying mode number on command line
>   efi/gop: Allow specifying mode by <xres>x<yres>
>   efi/gop: Allow specifying depth as well as resolution
>   efi/gop: Allow automatically choosing the best mode
>
>  Documentation/fb/efifb.rst                    |  33 +-
>  arch/x86/include/asm/efi.h                    |   4 +
>  .../firmware/efi/libstub/efi-stub-helper.c    |   3 +
>  drivers/firmware/efi/libstub/efistub.h        |   8 +-
>  drivers/firmware/efi/libstub/gop.c            | 489 ++++++++++++++----
>  5 files changed, 428 insertions(+), 109 deletions(-)
>
>
> base-commit: d5528d5e91041e68e8eab9792ce627705a0ed273
> --
> 2.24.1
>