On Sat, Dec 05, 2020 at 08:59:55AM +0100, Enrico Weigelt, metux IT consult wrote:
> On 04.12.20 04:35, Jason Wang wrote:
>
> >> --- a/drivers/gpio/Kconfig
> >> +++ b/drivers/gpio/Kconfig
> >> @@ -1615,6 +1615,15 @@ config GPIO_MOCKUP
> >> Â Â Â Â Â Â Â tools/testing/selftests/gpio/gpio-mockup.sh. Reference the
> >> usage in
> >> Â Â Â Â Â Â Â it.
> >> Â +config GPIO_VIRTIO
> >> +Â Â Â tristate "VirtIO GPIO support"
> >> +Â Â Â depends on VIRTIO
> >
> >
> > Let's use select, since there's no prompt for VIRTIO and it doesn't have
> > any dependencies.
>
> whoops, it's not that simple:
>
> make: Entering directory '/home/nekrad/src/apu2-dev/pkg/kernel.apu2.git'
> make[1]: Entering directory
> '/home/nekrad/src/dk/DistroKit/platform-x86_64/build-target/linux-5.8.9-build'
> GEN Makefile
> drivers/gpu/drm/Kconfig:74:error: recursive dependency detected!
> drivers/gpu/drm/Kconfig:74: symbol DRM_KMS_HELPER is selected by
> DRM_VIRTIO_GPU
> drivers/gpu/drm/virtio/Kconfig:2: symbol DRM_VIRTIO_GPU depends on VIRTIO
> drivers/virtio/Kconfig:2: symbol VIRTIO is selected by GPIO_VIRTIO
> drivers/gpio/Kconfig:1618: symbol GPIO_VIRTIO depends on GPIOLIB
> drivers/gpio/Kconfig:14: symbol GPIOLIB is selected by I2C_MUX_LTC4306
> drivers/i2c/muxes/Kconfig:47: symbol I2C_MUX_LTC4306 depends on I2C
> drivers/i2c/Kconfig:8: symbol I2C is selected by FB_DDC
> drivers/video/fbdev/Kconfig:63: symbol FB_DDC depends on FB
> drivers/video/fbdev/Kconfig:12: symbol FB is selected by DRM_KMS_FB_HELPER
> drivers/gpu/drm/Kconfig:80: symbol DRM_KMS_FB_HELPER depends on
> DRM_KMS_HELPER
>
> Seems that we can only depend on or select some symbol - we run into
> huge trouble if thats mixed. Just changed DRM_VIRTIO_GPU to just select
> VIRIO instead of depending on it, and now it works.
>
> I've posted another patch for fixing drivers/gpu/drm/virtio/Kconfig
> to use 'select' instead of 'depends on'.
It seems a bit of a mess, at this point I'm not entirely sure when
should drivers select VIRTIO and when depend on it.
The text near it says:
# SPDX-License-Identifier: GPL-2.0-only
config VIRTIO
tristate
help
This option is selected by any driver which implements the virtio
bus, such as CONFIG_VIRTIO_PCI, CONFIG_VIRTIO_MMIO, CONFIG_RPMSG
or CONFIG_S390_GUEST.
Which seems clear enough and would indicate drivers for devices *behind*
the bus should not select VIRTIO and thus presumably should "depend on" it.
This is violated in virtio console and virtio fs drivers.
For console it says:
commit 9f30eb29c514589e16f2999ea070598583d1f6ec
Author: Michal Suchanek <msuchanek@xxxxxxx>
Date: Mon Aug 31 18:58:50 2020 +0200
char: virtio: Select VIRTIO from VIRTIO_CONSOLE.
Make it possible to have virtio console built-in when
other virtio drivers are modular.
Signed-off-by: Michal Suchanek <msuchanek@xxxxxxx>
Reviewed-by: Amit Shah <amit@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200831165850.26163-1-msuchanek@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
which seems kind of bogus - why do we care about allowing a builtin
virtio console driver if the pci virtio bus driver is a module?
There won't be any devices on the bus to attach to ...
And for virtio fs it was like this from the beginning.
I am inclined to fix console and virtio fs to depend on VIRTIO:
select is harder to use correctly ...
Jason?
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> Enrico Weigelt, metux IT consult
> Free software and Linux embedded engineering
> info@xxxxxxxxx -- +49-151-27565287
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