[PATCH 01/22] fb: amifb: Stop using platform_driver_probe()

[Geert Uytterhoeven]

Hi Uwe,

On Tue, Nov 7, 2023 at 10:20 AM Uwe Kleine-König
<u.kleine-koenig at pengutronix.de> wrote:
> On today's platforms the benefit of platform_driver_probe() isn't that
> relevant any more. It allows to drop some code after booting (or module
> loading) for .probe() and discard the .remove() function completely if
> the driver is built-in. This typically saves a few 100k.

Which is a lot on platforms with only a few MiBs of RAM...

> The downside of platform_driver_probe() is that the driver cannot be
> bound and unbound at runtime which is ancient and also slightly
> complicates testing. There are also thoughts to deprecate
> platform_driver_probe() because it adds some complexity in the driver
> core for little gain. Also many drivers don't use it correctly. This
> driver for example misses to mark the driver struct with __refdata which
> is needed to suppress a (W=1) modpost warning:
>
>         WARNING: modpost: drivers/video/fbdev/amifb: section mismatch in reference: amifb_driver+0x4 (section: .data) -> amifb_remove (section: .exit.text)
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>

Thanks for your patch!

> --- a/drivers/video/fbdev/amifb.c
> +++ b/drivers/video/fbdev/amifb.c
> @@ -3530,7 +3530,7 @@ static inline void chipfree(void)
>          * Initialisation
>          */
>
> -static int __init amifb_probe(struct platform_device *pdev)
> +static int amifb_probe(struct platform_device *pdev)

noreply at ellerman.id.au reported the following build failure for
e.g. m68k-defconfig in next-20231108:

WARNING: modpost: vmlinux: section mismatch in reference:
amifb_probe+0x15c (section: .text) -> ami_modedb (section: .init.data)
WARNING: modpost: vmlinux: section mismatch in reference:
amifb_probe+0x17a (section: .text) -> amifb_hfmin (section:
.init.data)
WARNING: modpost: vmlinux: section mismatch in reference:
amifb_probe+0x188 (section: .text) -> amifb_hfmax (section:
.init.data)
WARNING: modpost: vmlinux: section mismatch in reference:
amifb_probe+0x190 (section: .text) -> amifb_vfmin (section:
.init.data)
WARNING: modpost: vmlinux: section mismatch in reference:
amifb_probe+0x198 (section: .text) -> amifb_vfmax (section:
.init.data)
WARNING: modpost: vmlinux: section mismatch in reference:
amifb_probe+0x1ba (section: .text) -> ami_modedb (section: .init.data)
WARNING: modpost: vmlinux: section mismatch in reference:
amifb_probe+0x1c4 (section: .text) -> ami_modedb (section: .init.data)
WARNING: modpost: vmlinux: section mismatch in reference:
amifb_probe+0x1ca (section: .text) -> mode_option (section:
.init.data)
WARNING: modpost: vmlinux: section mismatch in reference:
amifb_probe+0x1ee (section: .text) -> ami_modedb (section: .init.data)
WARNING: modpost: vmlinux: section mismatch in reference:
amifb_probe+0x398 (section: .text) -> amifb_hfmin (section:
.init.data)
WARNING: modpost: vmlinux: section mismatch in reference:
amifb_probe+0x39e (section: .text) -> amifb_hfmax (section:
.init.data)
WARNING: modpost: vmlinux: section mismatch in reference:
amifb_probe+0x3a4 (section: .text) -> amifb_vfmin (section:
.init.data)
WARNING: modpost: vmlinux: section mismatch in reference:
amifb_probe+0x3aa (section: .text) -> amifb_vfmax (section:
.init.data)
WARNING: modpost: vmlinux: section mismatch in reference:
amifb_probe+0x3f0 (section: .text) -> mode_option (section:
.init.data)
ERROR: modpost: Section mismatches detected.

Gr{oetje,eeting}s,

                        Geert


--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds