linux-kernel - Re: [PATCH v2 1/1] video: Handle HAS

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Message-Id: <5c992610-0716-47d1-97f6-65901797aa8c@app.fastmail.com>
Date: Wed, 15 May 2024 07:47:29 +0000
From: "Arnd Bergmann" <arnd@...nel.org>
To: "Niklas Schnelle" <schnelle@...ux.ibm.com>, "Helge Deller" <deller@....de>
Cc: linux-fbdev@...r.kernel.org, dri-devel@...ts.freedesktop.org,
 "Heiko Carstens" <hca@...ux.ibm.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/1] video: Handle HAS_IOPORT dependencies

On Tue, May 14, 2024, at 13:08, Niklas Schnelle wrote:
> In a future patch HAS_IOPORT=n will disable inb()/outb() and friends at
> compile time. We thus need to #ifdef functions and their callsites which
> unconditionally use these I/O accessors. In the include/video/vga.h
> these are conveniently all those functions with the vga_io_* prefix.
>
> Co-developed-by: Arnd Bergmann <arnd@...nel.org>
> Signed-off-by: Arnd Bergmann <arnd@...nel.org>
> Signed-off-by: Niklas Schnelle <schnelle@...ux.ibm.com>
> ---
> Note: This patch does not depend any not-yet-mainline HAS_IOPORT changes
> and may be merged via subsystem specific trees at your earliest
> convenience.
>
> v1 -> v2:
> - Moved vga_mm_r(), vga_mm_w(), vga_mm_w_fast() above #ifdef CONFIG_HAS_IOPORT
>   to use them in with or without I/O port variants.
> - Duplicated vga_r(), vga_w(), vga_w_fast() functions as non-I/O port variants
>   to get rid of in-code #ifdef (Arnd)
> - Got rid of if (regbase) logic inversion needed for in-code #ifdef

Thanks for preparing the new version!

> diff --git a/include/video/vga.h b/include/video/vga.h
> index 947c0abd04ef..468764d6727a 100644
> --- a/include/video/vga.h
> +++ b/include/video/vga.h
> @@ -197,9 +197,26 @@ struct vgastate {
>  extern int save_vga(struct vgastate *state);
>  extern int restore_vga(struct vgastate *state);
> 
> +static inline unsigned char vga_mm_r (void __iomem *regbase, unsigned 
> short port)
> +{
> +	return readb (regbase + port);
> +}

My first thought was that this should use the normal whitespace,
but I guess the file is pretty consistent about the style here,
so I agree with your choice here.

      Arnd