Re: [PATCH 6/8] drm: decouple from CONFIG_FB
From: Sam Ravnborg <hidden>
Date: 2020-04-17 16:50:52
Also in:
dri-devel, linux-renesas-soc
Hi Arnd. On Fri, Apr 17, 2020 at 05:55:51PM +0200, Arnd Bergmann wrote:
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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 <redacted> Sam
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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 helpdiff --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