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? > >>Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and > >>replace them with 'select DRM_FBDEV_EMULATION'? > >> > >>Another option would be to provide #ifdef DRM_FBDEV_EMULATION wrap-arounds > >>for fb related function calls/declarations in each driver, something that's > >>already done for i915 and msm drivers. > > > >The problem with the patch as-is the massive amounts of selects the FB > >helper still has. We need to get rid of them so that when you disable > >fbdev emulation you can indeed disable fbcon and the entire fbdev > >subsystem. I've thought that remove the hidden symbol DRM_KMS_FB_HELPER > >and moving all the selects to DRM_FBDEV_EMULATION should work out? If that > >doesn't work we need to look again how to better stub things out I think. > > That's true. Also, as Jani pointed out, maybe it isn't the best idea to make > every kms driver select DRM_FBDEV_EMULATION? > > Maybe the drivers that are currently built with fbdev emulation by default > can add a 'depends on DRM_FBDEV_EMULATION'? Since the config defaults to y, > the drivers should run as is. Later, we could take up each driver and build > the fb stuff only when DRM_FBDEV_EMULATION is set, like how we do for i915 > and msm? Yeah we definitely can't mix select with a user-visible option. I think we just need to fix up the remaining functions and create stubs for them if needed and then drop all the selects. Well in DRM_FBDEV_EMULATION we should still select for fbcon since otherwise tons of bug reports about "where is my fbcon with kms?". -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
