Regression? omap2plus_defconfig bloat due drivers/media/Kconfig changes

Regression? omap2plus_defconfig bloat due drivers/media/Kconfig changes

[Jarkko Nikula]

Hi

I noticed omap2plus_defconfig build is much slower than before and I saw
during build many DVB drivers were compiled. Which made me thinking it
doesn't look right especially there are no changes in
arch/arm/configs/omap2plus_defconfig related to DVB.

I tracked manually last good and first bad
arch/arm/configs/omap2plus_defconfig change.

This was tested by "make ARCH=arm omap2plus_defconfig" and grepping is
CONFIG_DVB_CORE set in .config.

good: 8b136018da7b ("mm: rename CONFIG_PGTABLE_MAPPING to
CONFIG_ZSMALLOC_PGTABLE_MAPPING")
bad: 8aa6361f7251 ("ARM: omap2plus_defconfig: enable twl4030_madc as a
loadable module")

Then I started bisecting which commit adds CONFIG_DVB_CORE and found
commit 8e5b5d75e9d0 ("media: Kconfig: DVB support should be enabled for
Digital TV").

That alone didn't look the answer so bisected then commit adding
MEDIA_DIGITAL_TV_SUPPORT and found c6774ee035dc ("media: Kconfig: make
filtering devices optional").

I'm not familiar with media subsystem but after that commit bunch of
media drivers will get enabled when CONFIG_MEDIA_SUPPORT is set but not
CONFIG_MEDIA_SUPPORT_FILTER.

I don't know is that best to fix in omap2plus_defconfig or
drivers/media/Kconfig. Just thinking if there are other minimal
defconfigs with the same issue?

Jarkko

Re: Regression? omap2plus_defconfig bloat due drivers/media/Kconfig changes

[Sakari Ailus]

Heipparallaa!

On Sun, Jun 13, 2021 at 09:03:21PM +0300, Jarkko Nikula wrote:
> Hi
> 
> I noticed omap2plus_defconfig build is much slower than before and I saw
> during build many DVB drivers were compiled. Which made me thinking it
> doesn't look right especially there are no changes in
> arch/arm/configs/omap2plus_defconfig related to DVB.
> 
> I tracked manually last good and first bad
> arch/arm/configs/omap2plus_defconfig change.
> 
> This was tested by "make ARCH=arm omap2plus_defconfig" and grepping is
> CONFIG_DVB_CORE set in .config.
> 
> good: 8b136018da7b ("mm: rename CONFIG_PGTABLE_MAPPING to
> CONFIG_ZSMALLOC_PGTABLE_MAPPING")
> bad: 8aa6361f7251 ("ARM: omap2plus_defconfig: enable twl4030_madc as a
> loadable module")
> 
> Then I started bisecting which commit adds CONFIG_DVB_CORE and found
> commit 8e5b5d75e9d0 ("media: Kconfig: DVB support should be enabled for
> Digital TV").
> 
> That alone didn't look the answer so bisected then commit adding
> MEDIA_DIGITAL_TV_SUPPORT and found c6774ee035dc ("media: Kconfig: make
> filtering devices optional").
> 
> I'm not familiar with media subsystem but after that commit bunch of
> media drivers will get enabled when CONFIG_MEDIA_SUPPORT is set but not
> CONFIG_MEDIA_SUPPORT_FILTER.
> 
> I don't know is that best to fix in omap2plus_defconfig or
> drivers/media/Kconfig. Just thinking if there are other minimal
> defconfigs with the same issue?

There was a change how the drivers for these little bits of hardware are
selected, enabling them all by default. So things generally work
differently they did before... One option would be to enable
MEDIA_SUPPORT_FILTER in the configuration, so only those devices that
you're interested would be supported.

-- 
Terveisin,

Sakari Ailus