Messages in this thread | | | Subject | Re: [PATCH v2 2/2] drivers: gpio: add virtio-gpio guest driver | From | Jason Wang <> | Date | Mon, 7 Dec 2020 11:12:50 +0800 |
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On 2020/12/6 上午3:32, Michael S. Tsirkin wrote: > 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@suse.de> > 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@suse.de> > Reviewed-by: Amit Shah <amit@kernel.org> > Link: https://lore.kernel.org/r/20200831165850.26163-1-msuchanek@suse.de > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > 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 ...
For testing like switching bus from pci to MMIO?
> 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?
I think it works, but we need a prompt for VIRTIO otherwise there's no way to enable it.
Thanks
> > >> -- >> --- >> Hinweis: unverschlüsselte E-Mails können leicht abgehört und manipuliert >> werden ! Für eine vertrauliche Kommunikation senden Sie bitte ihren >> GPG/PGP-Schlüssel zu. >> --- >> Enrico Weigelt, metux IT consult >> Free software and Linux embedded engineering >> info@metux.net -- +49-151-27565287
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