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From: Ard Biesheuvel <ardb@kernel.org>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Hans de Goede <hdegoede@redhat.com>,
	linux-efi <linux-efi@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 00/14] efi/gop: Refactoring + mode-setting feature
Date: Thu, 26 Mar 2020 00:36:25 +0100	[thread overview]
Message-ID: <CAMj1kXHPmtYgoUViF4baVHfy178ef8u57wJgqcZVagGTAuP3iQ@mail.gmail.com> (raw)
In-Reply-To: <20200325221007.GA290267@rani.riverdale.lan>

On Wed, 25 Mar 2020 at 23:10, Arvind Sankar <nivedita@alum.mit.edu> wrote:
>
> On Wed, Mar 25, 2020 at 05:41:43PM +0100, Ard Biesheuvel wrote:
> > On Fri, 20 Mar 2020 at 03:00, Arvind Sankar <nivedita@alum.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@intel.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.
> >
>
> I don't think so -- next_arg is for parsing space-separated param=value
> pairs, so efi_parse_options can use it, but it doesn't work for the
> comma-separated options we'll have within the value.
>
> parse_option_str would only work for the "auto" option, but it scans the
> entire option string and just returns whether it was there or not, so it
> wouldn't be too useful either, since we have to check for the other
> possibilities anyway.
>
> It would be nice to have a more generic library for cmdline parsing,
> there are a lot of places that have to open-code option parsing like
> this.
>
> There's one thing I noticed while working at this, btw. The Makefile
> specifies -ffreestanding, but at least x86 builds without having to
> specify that. With -ffreestanding, the compiler doesn't optimize string
> functions -- strlen(string literal) into a compile-time constant, for
> eg. A couple hundred bytes or so can be saved by removing that option,
> if it also works for ARM.

Yes, -ffreestanding implies -fno-builtin, which means that the
compiler cannot assume it knows (and can optimize away) the behavior
of strlen(), memset(), etc.

  reply	other threads:[~2020-03-25 23:36 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-19 19:28 [PATCH 00/14] efi/gop: Refactoring + mode-setting feature Arvind Sankar
2020-03-19 19:28 ` [PATCH 01/14] efi/gop: Remove redundant current_fb_base Arvind Sankar
2020-03-19 19:28 ` [PATCH 02/14] efi/gop: Move check for framebuffer before con_out Arvind Sankar
2020-03-19 19:28 ` [PATCH 03/14] efi/gop: Get mode information outside the loop Arvind Sankar
2020-03-19 19:28 ` [PATCH 04/14] efi/gop: Factor out locating the gop into a function Arvind Sankar
2020-03-19 19:28 ` [PATCH 05/14] efi/gop: Slightly re-arrange logic of find_gop Arvind Sankar
2020-03-19 19:28 ` [PATCH 06/14] efi/gop: Move variable declarations into loop block Arvind Sankar
2020-03-19 19:28 ` [PATCH 07/14] efi/gop: Use helper macros for populating lfb_base Arvind Sankar
2020-03-19 19:28 ` [PATCH 08/14] efi/gop: Use helper macros for find_bits Arvind Sankar
2020-03-19 19:28 ` [PATCH 09/14] efi/gop: Remove unreachable code from setup_pixel_info Arvind Sankar
2020-03-19 19:28 ` [PATCH 10/14] efi/gop: Add prototypes for query_mode and set_mode Arvind Sankar
2020-03-19 19:28 ` [PATCH 11/14] efi/gop: Allow specifying mode number on command line Arvind Sankar
2020-03-19 22:53   ` kbuild test robot
2020-03-20  1:09   ` kbuild test robot
2020-03-20 14:36   ` Dan Carpenter
2020-03-20 17:51     ` Arvind Sankar
2020-03-19 19:28 ` [PATCH 12/14] efi/gop: Allow specifying mode by <xres>x<yres> Arvind Sankar
2020-03-19 19:28 ` [PATCH 13/14] efi/gop: Allow specifying depth as well as resolution Arvind Sankar
2020-03-19 19:28 ` [PATCH 14/14] efi/gop: Allow automatically choosing the best mode Arvind Sankar
2020-03-19 20:02 ` [PATCH 00/14] efi/gop: Refactoring + mode-setting feature Ard Biesheuvel
2020-03-20  2:00 ` [PATCH v2 " Arvind Sankar
2020-03-25 16:41   ` Ard Biesheuvel
2020-03-25 22:10     ` Arvind Sankar
2020-03-25 23:36       ` Ard Biesheuvel [this message]
2020-03-26 10:41         ` Ard Biesheuvel
2020-03-28 16:06           ` efi/gop: skip cur_mode in choose_mode_auto Arvind Sankar
2020-03-28 16:06             ` [PATCH v3] efi/gop: Allow automatically choosing the best mode Arvind Sankar
2020-03-29  7:47             ` efi/gop: skip cur_mode in choose_mode_auto Ard Biesheuvel
2020-03-26 23:56         ` [PATCH v2 00/14] efi/gop: Refactoring + mode-setting feature Arvind Sankar
2020-03-28 15:43           ` Ard Biesheuvel
2020-03-25 16:50   ` Hans de Goede
2020-03-25 22:13     ` Arvind Sankar
2020-03-20  2:00 ` [PATCH v2 01/14] efi/gop: Remove redundant current_fb_base Arvind Sankar
2020-03-20  2:00 ` [PATCH v2 02/14] efi/gop: Move check for framebuffer before con_out Arvind Sankar
2020-03-20  2:00 ` [PATCH v2 03/14] efi/gop: Get mode information outside the loop Arvind Sankar
2020-03-20  2:00 ` [PATCH v2 04/14] efi/gop: Factor out locating the gop into a function Arvind Sankar
2020-03-20  2:00 ` [PATCH v2 05/14] efi/gop: Slightly re-arrange logic of find_gop Arvind Sankar
2020-03-20  2:00 ` [PATCH v2 06/14] efi/gop: Move variable declarations into loop block Arvind Sankar
2020-03-20  2:00 ` [PATCH v2 07/14] efi/gop: Use helper macros for populating lfb_base Arvind Sankar
2020-03-20  2:00 ` [PATCH v2 08/14] efi/gop: Use helper macros for find_bits Arvind Sankar
2020-03-20  2:00 ` [PATCH v2 09/14] efi/gop: Remove unreachable code from setup_pixel_info Arvind Sankar
2020-03-20  2:00 ` [PATCH v2 10/14] efi/gop: Add prototypes for query_mode and set_mode Arvind Sankar
2020-03-20  2:00 ` [PATCH v2 11/14] efi/gop: Allow specifying mode number on command line Arvind Sankar
2020-03-20  2:00 ` [PATCH v2 12/14] efi/gop: Allow specifying mode by <xres>x<yres> Arvind Sankar
2020-03-20  2:00 ` [PATCH v2 13/14] efi/gop: Allow specifying depth as well as resolution Arvind Sankar
2020-03-20  2:00 ` [PATCH v2 14/14] efi/gop: Allow automatically choosing the best mode Arvind Sankar

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