On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote: > > > On 03/11/2015 08:47 PM, Daniel Vetter wrote: > >On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote: > >> > >> > >>On 03/10/2015 05:47 PM, Daniel Vetter wrote: > >>>On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote: > >>>>On 03/10/2015 03:35 PM, Daniel Vetter wrote: > >>>>>On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote: > >>>>>>On 03/10/2015 03:17 PM, Daniel Vetter wrote: > >>>>>>>On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote: > >>>>>>>>diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig > >>>>>>>>index 151a050..38f83a0 100644 > >>>>>>>>--- a/drivers/gpu/drm/Kconfig > >>>>>>>>+++ b/drivers/gpu/drm/Kconfig > >>>>>>>>@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER > >>>>>>>> help > >>>>>>>> FBDEV helpers for KMS drivers. > >>>>>>>> > >>>>>>>>+config DRM_FBDEV_EMULATION > >>>>>>>>+ bool "Enable legacy fbdev support for your modesetting driver" > >>>>>>>>+ depends on DRM > >>>>>>>>+ select DRM_KMS_HELPER > >>>>>>>>+ select DRM_KMS_FB_HELPER > >>>>>>>>+ select FB_SYS_FILLRECT > >>>>>>>>+ select FB_SYS_COPYAREA > >>>>>>>>+ select FB_SYS_IMAGEBLIT > >>>>>>>>+ select FB_SYS_FOPS > >>>>>>>>+ select FB_CFB_FILLRECT > >>>>>>>>+ select FB_CFB_COPYAREA > >>>>>>>>+ select FB_CFB_IMAGEBLIT > >>>>>>>>+ default y > >>>>>>>>+ help > >>>>>>>>+ Choose this option if you have a need for the legacy fbdev > >>>>>>>>+ support. Note that this support also provide the linux console > >>>>>>>>+ support on top of your modesetting driver. > >>>>>>> > >>>>>>>Maybe clarify that for linux console support you also need > >>>>>>>CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough. > >>>>>> > >>>>>>DRM_KMS_FB_HELPER selects that for us, right? > >>>>> > >>>>>Hm right I've missed that. Reminds me that you need one more patch at the > >>>>>end to remove all the various select DRM_KMS_FB_HELPER from all drm > >>>>>drivers. Otherwise this knob here won't work by default if you e.g. select > >>>>>radeon. In general we can't mix explicit options with menu entries with a > >>>>>select. > >>>> > >>>>I was trying that out. Removing DRM_KMS_FB_HELPER and having > >>>>DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in > >>>>their respective xyz_fbdev.c files. > >>> > >>>But with the stubbed out functions that should work, right? Why doesn't > >>>it? > >> > >>There are still calls to functions from fb core like fb_set_suspend and > >>register_framebuffer which aren't covered by the drm fb helper functions. > > > >Hm, sounds like we need another patch to stub out fb_set_suspend when > >fbdev isn't enabled. Is there anything else? > > There are a handful of fb core functions which are called by drm drivers: > > fb_alloc_cmap/fb_dealloc_cmap > > fb_sys_read/fb_sys_write > > register_framebuffer/unregister_framebuffer/unlink_framebuffer/ > remove_conflicting_framebuffers > > fb_set_suspend > > fb_deferred_io_init/fb_deferred_io_cleanup > > framebuffer_alloc/framebuffer_release Hm yeah that's somewhat annoying indeed. What about the following: 1. We move all the #include <linux/fb.h> from drivers into drm_fb_helper.h 2. Then we add stubs for these functions in drm_fb_helper.h, like this #if defined(CONFIG_FB) #include <linux/fb.h> #else /* static inline stubs for all the fb stuff used by kms drivers */ #endif Imo this makes sense since kms drivers really have a bit a special situation with fbdev. They're not full-blown fbdev drivers and can be useful fully without fbdev. What do you think? -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
