| Message ID | 20200417155553.675905-7-arnd@arndb.de (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Kieran Bingham |
| Headers | show |
| Series | drm, fbdev: rework dependencies | expand |
Hi Arnd. On Fri, Apr 17, 2020 at 05:55:51PM +0200, Arnd Bergmann wrote: > CONFIG_DRM_KMS_FB_HELPER selects CONFIG_FB, which is something it > really should not, to avoid circular dependencies and accidentally > including potentially dangerous user interfaces in the kernel, > so change this into a 'depends on' check. > > Two device drivers currently select CONFIG_DRM_KMS_FB_HELPER, but > as far as I can tell, they do not really need to any more, so those > selects can be removed. > > This leaves DRM_FBDEV_EMULATION as the only thing that rightfully > selects CONFIG_DRM_KMS_FB_HELPER, and this now has to depend on > CONFIG_FB and its dependencies. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/gpu/drm/Kconfig | 5 +++-- > drivers/gpu/drm/mxsfb/Kconfig | 1 - > drivers/gpu/drm/zte/Kconfig | 1 - > 3 files changed, 3 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig > index 43594978958e..7c3109133685 100644 > --- a/drivers/gpu/drm/Kconfig > +++ b/drivers/gpu/drm/Kconfig > @@ -80,7 +80,7 @@ config DRM_KMS_HELPER > config DRM_KMS_FB_HELPER > bool > depends on DRM_KMS_HELPER > - select FB > + depends on FB > select FRAMEBUFFER_CONSOLE if !EXPERT > select FRAMEBUFFER_CONSOLE_DETECT_PRIMARY if FRAMEBUFFER_CONSOLE > select FB_SYS_FOPS > @@ -111,7 +111,8 @@ config DRM_DEBUG_DP_MST_TOPOLOGY_REFS > > config DRM_FBDEV_EMULATION > bool "Enable legacy fbdev support for your modesetting driver" > - depends on DRM > + depends on DRM && FB > + depends on FB=y || DRM=m > select DRM_KMS_HELPER > select DRM_KMS_FB_HELPER > default y This statement: depends on DRM && FB tell us that both symbols must be either y or m. Any combination of y and m will do the trick Then we have this statement: depends on FB=y || DRM=m It tells us that either FB equals y or DRM equals m. So we have following table FB DRM Result n n n n y n n m n y n n y y y y m y m n n m y N m m y So what this try to say is that we cannot have FB a module while DRM is built-in (marked N in the above). Could you explain in the changelog why this combination is not good. (Or tell me if my analysis was flawed). With this fixed (assuming I am right): Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Sam > diff --git a/drivers/gpu/drm/mxsfb/Kconfig b/drivers/gpu/drm/mxsfb/Kconfig > index 0dca8f27169e..33916b7b2c50 100644 > --- a/drivers/gpu/drm/mxsfb/Kconfig > +++ b/drivers/gpu/drm/mxsfb/Kconfig > @@ -10,7 +10,6 @@ config DRM_MXSFB > depends on COMMON_CLK > select DRM_MXS > select DRM_KMS_HELPER > - select DRM_KMS_FB_HELPER > select DRM_KMS_CMA_HELPER > select DRM_PANEL > help > diff --git a/drivers/gpu/drm/zte/Kconfig b/drivers/gpu/drm/zte/Kconfig > index 90ebaedc11fd..aa8594190b50 100644 > --- a/drivers/gpu/drm/zte/Kconfig > +++ b/drivers/gpu/drm/zte/Kconfig > @@ -3,7 +3,6 @@ config DRM_ZTE > tristate "DRM Support for ZTE SoCs" > depends on DRM && ARCH_ZX > select DRM_KMS_CMA_HELPER > - select DRM_KMS_FB_HELPER > select DRM_KMS_HELPER > select SND_SOC_HDMI_CODEC if SND_SOC > select VIDEOMODE_HELPERS > -- > 2.26.0 > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
On Fri, Apr 17, 2020 at 6:50 PM Sam Ravnborg <sam@ravnborg.org> wrote: > > So what this try to say is that we cannot have FB a module while DRM is > built-in (marked N in the above). Correct > > Could you explain in the changelog why this combination is not good. > (Or tell me if my analysis was flawed). I agree in hindsight this was less obvious than I thought ;-) Added this text to the changelog: | When CONFIG_FB is a loadable module, DRM_KMS_FB_HELPER cannot be | part of the built-in subsystem, so add dependency to ensure this | can only be enabled if the DRM module can successfully be linked. and this comment in the Kconfig file: @@ -112,7 +112,7 @@ config DRM_DEBUG_DP_MST_TOPOLOGY_REFS config DRM_FBDEV_EMULATION bool "Enable legacy fbdev support for your modesetting driver" depends on DRM && FB - depends on FB=y || DRM=m + depends on FB=y || DRM=m # DRM_KMS_FB_HELPER links against FB select DRM_KMS_HELPER select DRM_KMS_FB_HELPER default y Let me know if you think those changes are sufficient > With this fixed (assuming I am right): > Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Thanks! Arnd
Hi Arnd. On Fri, Apr 17, 2020 at 10:03:23PM +0200, Arnd Bergmann wrote: > On Fri, Apr 17, 2020 at 6:50 PM Sam Ravnborg <sam@ravnborg.org> wrote: > > > > > So what this try to say is that we cannot have FB a module while DRM is > > built-in (marked N in the above). > > Correct > > > > > Could you explain in the changelog why this combination is not good. > > (Or tell me if my analysis was flawed). > > I agree in hindsight this was less obvious than I thought ;-) > > Added this text to the changelog: > > | When CONFIG_FB is a loadable module, DRM_KMS_FB_HELPER cannot be > | part of the built-in subsystem, so add dependency to ensure this > | can only be enabled if the DRM module can successfully be linked. > > and this comment in the Kconfig file: > > @@ -112,7 +112,7 @@ config DRM_DEBUG_DP_MST_TOPOLOGY_REFS > config DRM_FBDEV_EMULATION > bool "Enable legacy fbdev support for your modesetting driver" > depends on DRM && FB > - depends on FB=y || DRM=m > + depends on FB=y || DRM=m # DRM_KMS_FB_HELPER links against FB > select DRM_KMS_HELPER > select DRM_KMS_FB_HELPER > default y > > Let me know if you think those changes are sufficient > > > With this fixed (assuming I am right): > > Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Yes, that explains it nicely - thanks. But unless Daniel decides otherwise we do not get it applied. He was not too happy with it. Sam
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index 43594978958e..7c3109133685 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -80,7 +80,7 @@ config DRM_KMS_HELPER config DRM_KMS_FB_HELPER bool depends on DRM_KMS_HELPER - select FB + depends on FB select FRAMEBUFFER_CONSOLE if !EXPERT select FRAMEBUFFER_CONSOLE_DETECT_PRIMARY if FRAMEBUFFER_CONSOLE select FB_SYS_FOPS @@ -111,7 +111,8 @@ config DRM_DEBUG_DP_MST_TOPOLOGY_REFS config DRM_FBDEV_EMULATION bool "Enable legacy fbdev support for your modesetting driver" - depends on DRM + depends on DRM && FB + depends on FB=y || DRM=m select DRM_KMS_HELPER select DRM_KMS_FB_HELPER default y diff --git a/drivers/gpu/drm/mxsfb/Kconfig b/drivers/gpu/drm/mxsfb/Kconfig index 0dca8f27169e..33916b7b2c50 100644 --- a/drivers/gpu/drm/mxsfb/Kconfig +++ b/drivers/gpu/drm/mxsfb/Kconfig @@ -10,7 +10,6 @@ config DRM_MXSFB depends on COMMON_CLK select DRM_MXS select DRM_KMS_HELPER - select DRM_KMS_FB_HELPER select DRM_KMS_CMA_HELPER select DRM_PANEL help diff --git a/drivers/gpu/drm/zte/Kconfig b/drivers/gpu/drm/zte/Kconfig index 90ebaedc11fd..aa8594190b50 100644 --- a/drivers/gpu/drm/zte/Kconfig +++ b/drivers/gpu/drm/zte/Kconfig @@ -3,7 +3,6 @@ config DRM_ZTE tristate "DRM Support for ZTE SoCs" depends on DRM && ARCH_ZX select DRM_KMS_CMA_HELPER - select DRM_KMS_FB_HELPER select DRM_KMS_HELPER select SND_SOC_HDMI_CODEC if SND_SOC select VIDEOMODE_HELPERS
CONFIG_DRM_KMS_FB_HELPER selects CONFIG_FB, which is something it really should not, to avoid circular dependencies and accidentally including potentially dangerous user interfaces in the kernel, so change this into a 'depends on' check. Two device drivers currently select CONFIG_DRM_KMS_FB_HELPER, but as far as I can tell, they do not really need to any more, so those selects can be removed. This leaves DRM_FBDEV_EMULATION as the only thing that rightfully selects CONFIG_DRM_KMS_FB_HELPER, and this now has to depend on CONFIG_FB and its dependencies. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/gpu/drm/Kconfig | 5 +++-- drivers/gpu/drm/mxsfb/Kconfig | 1 - drivers/gpu/drm/zte/Kconfig | 1 - 3 files changed, 3 insertions(+), 4 deletions(-)