Jason Wang
2020-Dec-07 03:16 UTC
[PATCH v2 2/2] drivers: gpio: add virtio-gpio guest driver
On 2020/12/6 ??4:05, Enrico Weigelt, metux IT consult wrote:> On 05.12.20 20:32, Michael S. Tsirkin wrote: > > Hi, > >> 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. > if VIRTIO just enables something that could be seen as library > functions, then select should be right, IMHO. > >> The text near it says: >> >> # SPDX-License-Identifier: GPL-2.0-only >> config VIRTIO >> tristate > oh, wait, doesn't have an menu text, so we can't even explicitly enable > it (not shown in menu) - only implicitly. Which means that some other > option must select it, in order to become availe at all, and in order > to make others depending on it becoming available. > > IMHO, therefore select is the correct approach. > > >> 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. > See above: NAK. because it can't even be enabled directly (by the user). > If it wasn't meant otherwise, we'd have to add an menu text. > >> For console it says: >> >> commit 9f30eb29c514589e16f2999ea070598583d1f6ec >> Author: Michal Suchanek <msuchanek at 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 at suse.de> >> Reviewed-by: Amit Shah <amit at kernel.org> >> Link: https://lore.kernel.org/r/20200831165850.26163-1-msuchanek at suse.de >> Signed-off-by: Greg Kroah-Hartman <gregkh at 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 ... > When using other transports ? > In my current project, eg. I'm using mmio - my kernel has pci completely > disabled. > >> I am inclined to fix console and virtio fs to depend on VIRTIO: >> select is harder to use correctly ... > I don't thinkt that would be good - instead everybody should just select > VIRTIO, never depend on it (maybe depend on VIRTIO_MENU instead)I'm fine with either. Though I prefer to use select but it looks to me adding a prompt and use enable would be easier. Thanks> > > --mtx >