[PATCH]"drm: change DRM_MIPI_DSI module type from "bool" to "tristate".
I think "installing a kernel with my changes for both drm and i915" takes more time and effort to complete than "only updating DRM/i915 modules without rebuilding the whole kernel". In some cases, that's beneficial. Also reloadablility is always a good thing to have and I truly hope Hajda/Iwai's patches would be accepted and merged. No downside of it after all. Regards, Sun, Jing -Original Message- From: Daniel Vetter [mailto:daniel.vet...@ffwll.ch] On Behalf Of Daniel Vetter Sent: Wednesday, October 12, 2016 2:52 PM To: Sun, Jing A Cc: Andrzej Hajda; Jani Nikula; Takashi Iwai; Emil Velikov; linux-kernel at vger.kernel.org; dri-devel at lists.freedesktop.org; Vetter, Daniel; Thierry Reding Subject: Re: [PATCH]"drm: change DRM_MIPI_DSI module type from "bool" to "tristate". On Wed, Oct 12, 2016 at 03:08:24AM +, Sun, Jing A wrote: > Interestingly, I am able to reload i915 and drm. Our CI has tests for > i915 unload/reload, but does not check drm. In any case the config > problem should not impact the reloadability of i915. > == > Sorry that I didn't make myself clear. In order to replace the default > i915 module with an updated one, the related DRM modules also need to > be updated to match the updated i915, hence the restriction. Just to avoid tears in the future: If you plan to ship this in product, you won't ship. And for debugging, just install a kernel with your changes for both drm and i915. In short, your use-case isn't really valid (but we could still make the dsi code modular if people feel like). -Daniel > > Regards, > Sun, Jing > > > -Original Message- > From: Andrzej Hajda [mailto:a.hajda at samsung.com] > Sent: Tuesday, October 11, 2016 5:53 PM > To: Jani Nikula; Sun, Jing A; Takashi Iwai > Cc: airlied at linux.ie; Vetter, Daniel; linux-kernel at vger.kernel.org; > dri-devel at lists.freedesktop.org; Thierry Reding; Emil Velikov > Subject: Re: [PATCH]"drm: change DRM_MIPI_DSI module type from "bool" to > "tristate". > > On 11.10.2016 11:33, Jani Nikula wrote: > > On Tue, 11 Oct 2016, "Sun, Jing A" wrote: > >> It's needed that DRM Driver module could be removed and reloaded > >> after kernel booting on the projects that I have been working on, > >> and I hope such module type change could be accepted. Looks like > >> Iwai has similar change request as well. Would you please review it > >> and let us know if any concerns? > > Looking at the Kconfig, selecting CONFIG_DRM_MIPI_DSI is against the > > recommendations of Documentation/kbuild/kconfig-language.txt: > > > > select should be used with care. select will force > > a symbol to a value without visiting the dependencies. > > By abusing select you are able to select a symbol FOO even > > if FOO depends on BAR that is not set. > > In general use select only for non-visible symbols > > (no prompts anywhere) and for symbols with no dependencies. > > That will limit the usefulness but on the other hand avoid > > the illegal configurations all over. > > All existing drivers which selects DRM_MIPI_DSI also depends on DRM. > So the dependency is always true. I am not sure if it could not change > in the future, but in such case mipi_dsi bus should be completely > detached from DRM framework, I hope we have not such case yet :) > > > > > Indeed, you may end up with CONFIG_DRM_MIPI_DSI=y and CONFIG_DRM=m, > > which violates DRM_MIPI_DSI dependency on CONFIG_DRM. This is broken > > and should be fixed. The suggested patch does *not* fix this issue. > > At the moment it should not be possible. > > Regards > Andrzej > > ___ > dri-devel mailing list > dri-devel at lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
[PATCH]"drm: change DRM_MIPI_DSI module type from "bool" to "tristate".
Interestingly, I am able to reload i915 and drm. Our CI has tests for i915 unload/reload, but does not check drm. In any case the config problem should not impact the reloadability of i915. == Sorry that I didn't make myself clear. In order to replace the default i915 module with an updated one, the related DRM modules also need to be updated to match the updated i915, hence the restriction. Regards, Sun, Jing -Original Message- From: Andrzej Hajda [mailto:a.ha...@samsung.com] Sent: Tuesday, October 11, 2016 5:53 PM To: Jani Nikula; Sun, Jing A; Takashi Iwai Cc: airlied at linux.ie; Vetter, Daniel; linux-kernel at vger.kernel.org; dri-devel at lists.freedesktop.org; Thierry Reding; Emil Velikov Subject: Re: [PATCH]"drm: change DRM_MIPI_DSI module type from "bool" to "tristate". On 11.10.2016 11:33, Jani Nikula wrote: > On Tue, 11 Oct 2016, "Sun, Jing A" wrote: >> It's needed that DRM Driver module could be removed and reloaded >> after kernel booting on the projects that I have been working on, and >> I hope such module type change could be accepted. Looks like Iwai has >> similar change request as well. Would you please review it and let us >> know if any concerns? > Looking at the Kconfig, selecting CONFIG_DRM_MIPI_DSI is against the > recommendations of Documentation/kbuild/kconfig-language.txt: > > select should be used with care. select will force > a symbol to a value without visiting the dependencies. > By abusing select you are able to select a symbol FOO even > if FOO depends on BAR that is not set. > In general use select only for non-visible symbols > (no prompts anywhere) and for symbols with no dependencies. > That will limit the usefulness but on the other hand avoid > the illegal configurations all over. All existing drivers which selects DRM_MIPI_DSI also depends on DRM. So the dependency is always true. I am not sure if it could not change in the future, but in such case mipi_dsi bus should be completely detached from DRM framework, I hope we have not such case yet :) > > Indeed, you may end up with CONFIG_DRM_MIPI_DSI=y and CONFIG_DRM=m, > which violates DRM_MIPI_DSI dependency on CONFIG_DRM. This is broken > and should be fixed. The suggested patch does *not* fix this issue. At the moment it should not be possible. Regards Andrzej
[PATCH]"drm: change DRM_MIPI_DSI module type from "bool" to "tristate".
Dear Maintainers, It's needed that DRM Driver module could be removed and reloaded after kernel booting on the projects that I have been working on, and I hope such module type change could be accepted. Looks like Iwai has similar change request as well. Would you please review it and let us know if any concerns? Regards, Sun, Jing -Original Message- From: Takashi Iwai [mailto:ti...@suse.de] Sent: Monday, October 10, 2016 5:57 PM To: Jani Nikula Cc: Sun, Jing A; airlied at linux.ie; Vetter, Daniel; linux-kernel at vger.kernel.org; dri-devel at lists.freedesktop.org; Takashi Iwai; a.hajda at samsung.com; Thierry Reding Subject: Re: [PATCH]"drm: change DRM_MIPI_DSI module type from "bool" to "tristate". On Mon, 10 Oct 2016 10:28:31 +0200, Jani Nikula wrote: > > On Mon, 10 Oct 2016, "Sun, Jing A" wrote: > > Dear Maintainers, > > > > Please kindly review my patch as below. It's based on the mainline branch. > > > > From b401009f79883ac5e9d41525c9d54b800ece2e22 Mon Sep 17 00:00:00 > > 2001 > > From: Jing SUN > > Date: Mon, 10 Oct 2016 14:06:54 +0800 > > Subject: [PATCH 1/1] drm: change DRM_MIPI_DSI module type from > > "bool" to "tristate". > > > > A lot of drm driver modules, which are designed to be loadable, > > select DRM_MIPI_DSI, while that being "bool" prevents those from > > getting reloaded. > > You're missing some lists and people from distribution, added now. > > See the discussion starting at [1]. I don't know if anything has > happened since then. Takashi? Unfortunately, nothing seems to have happened since my last patch due to little interest. I'd be glad if the patch is revived. (BTW, I'm traveling in these two weeks, so the further reply will be delayed.) thanks, Takashi > > BR, > Jani. > > > [1] http://lkml.kernel.org/r/s5hh9bhvj7j.wl-tiwai at suse.de > > > > > > Signed-off-by: Jing SUN > > --- > > drivers/gpu/drm/Kconfig | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index > > fc35731..67668a0 100644 > > --- a/drivers/gpu/drm/Kconfig > > +++ b/drivers/gpu/drm/Kconfig > > @@ -22,7 +22,7 @@ menuconfig DRM > > (/dev/agpgart) support if it is available for your platform. > > > > config DRM_MIPI_DSI > > - bool > > + tristate > > depends on DRM > > > > config DRM_DP_AUX_CHARDEV > > -- > Jani Nikula, Intel Open Source Technology Center >
