[Intel-gfx] [PATCH] drm/i915: tell the user if both KMS and UMS are disabled

[Daniel Vetter]

On Tue, May 27, 2014 at 07:24:12PM +0300, Jani Nikula wrote:
> If both KMS is disabled (by i915.modeset=0 or nomodeset parameters) and
> UMS is disabled (by CONFIG_DRM_I915_UMS=n, the default), the user might
> not be aware his setup is not supported. Inform the users (and, by
> extension, the poor i915 developers having to read their dmesgs in bug
> reports) why their graphics experience might be lacking.
> 
> A similar message was added on the UMS path in
> commit e147accbd19f55489dabdcc4dc3551cc3e3f2553
> Author: Jani Nikula <jani.nikula at intel.com>
> Date:   Thu Oct 10 15:25:37 2013 +0300
> 
>     drm/i915: tell the user KMS is required for gen6+
> 
> but it won't be reached if CONFIG_DRM_I915_UMS=n since
> commit b30324adaf8d2e5950a602bde63030d15a61826f
> Author: Daniel Vetter <daniel.vetter at ffwll.ch>
> Date:   Wed Nov 13 22:11:25 2013 +0100
> 
>     drm/i915: Deprecated UMS support
> 
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>

Hm, the idea is that this fails _very_ silently so that people only send
us regression reports if they actually notice something. Since if there
are still people out there which needs UMS, we can't yet rip it out.
-Daniel

> ---
>  drivers/gpu/drm/i915/i915_drv.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 8949fd26b0ea..f0f690776d45 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1584,6 +1584,8 @@ static int __init i915_init(void)
>  	if (!(driver.driver_features & DRIVER_MODESET)) {
>  		driver.get_vblank_timestamp = NULL;
>  #ifndef CONFIG_DRM_I915_UMS
> +		DRM_INFO("Kernel modesetting (KMS) and userspace modesetting (UMS) disabled\n");
> +		DRM_INFO("See CONFIG_DRM_I915_UMS, CONFIG_DRM_I915_KMS, nomodeset, and i915.modeset parameters\n");
>  		/* Silently fail loading to not upset userspace. */
>  		return 0;
>  #endif
> -- 
> 1.9.1
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch