On Mon, Dec 07, 2020 at 11:12:50AM +0800, Jason Wang wrote: > > 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 > > > > >        tools/testing/selftests/gpio/gpio-mockup.sh. Reference the > > > > > usage in > > > > >        it. > > > > >  +config GPIO_VIRTIO > > > > > +   tristate "VirtIO GPIO support" > > > > > +   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 ... > > > For testing like switching bus from pci to MMIO? Not sure I understand ... can you give an example? > > > 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 That's even messier. No one needs VIRTIO core by itself - it's only used by transports and drivers. > > > > > > > > -- > > > --- > > > 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@xxxxxxxxx -- +49-151-27565287
