On Wed, Jul 29, 2015 at 09:49:04AM +0530, Archit Taneja wrote:
On 07/29/2015 12:16 AM, Daniel Vetter wrote:
On Wed, Jul 22, 2015 at 02:58:01PM +0530, Archit Taneja wrote:
Some drm drivers call remove_conflicting_framebuffers. Create a drm_fb_helper function that wraps around these calls.
This is part of an effort to prevent drm drivers from calling fbdev functions directly, in order to make fbdev emulation a top level drm option.
v2:
- Added kerneldocs
- Follow the drm way of aligning of arguments in func definitions
Signed-off-by: Archit Taneja architt@codeaurora.org
drivers/gpu/drm/drm_fb_helper.c | 15 +++++++++++++++ include/drm/drm_fb_helper.h | 4 ++++ 2 files changed, 19 insertions(+)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 9620aa5..86e4e2c 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -894,6 +894,21 @@ void drm_fb_helper_set_suspend(struct drm_fb_helper *fb_helper, int state) } EXPORT_SYMBOL(drm_fb_helper_set_suspend);
+/**
- drm_fb_helper_remove_conflicting_framebuffers - wrapper around
remove_conflicting_framebuffers
- @fb_helper: driver-allocated fbdev helper
- A wrapper around remove_conflicting_framebuffers implemented by fbdev core
- */
+int drm_fb_helper_remove_conflicting_framebuffers(struct apertures_struct *a,
const char *name,bool primary)+{
- return remove_conflicting_framebuffers(a, name, primary);
+} +EXPORT_SYMBOL(drm_fb_helper_remove_conflicting_framebuffers);
Chris Wilson reported on irc that if he builds with I915_FBDEV=n then there's a missing symbol problem here because i915 wants to kick out other framebuffers (well we have to for correctness) even when fbdev emulation is disabled. If you look at i915_dma.c you'll see that the call to remove_conflicting_framebuffers is conditional upon CONFIG_FB and not CONFIG_I915_FBDEV.
I think the proper solution here would be to provide a static inline helper for remove_conflicting_framebuffer itself when CONFIG_FB=n, since a all drivers who call this still want to call this even when fbdev emulation is disabled.
Plan B would be to move this into core drm and make the static inline one selected for CONFIG_FB=n. If you do that then maybe also rename it to drm_remove_conflicting_framebuffer since this really is only tangetial to fbdev emulation.
The remove_conflicting_framebuffers calls do_unregister_framebuffer(), which seems to be quite central to fb core, and can't just work without other fb core funcs.
What I don't get is, if legacy fb was never enabled, how did we end up registering fbs in the first place?
Could you briefly explain what these other 'framebuffers' are that remove_conflicting_framebuffers removes? The comments say that they are firmware allocated fbs. I'm not well versed with what happens in desktop graphics.
Following config is the relevant one:
CONFIG_FB=y CONFIG_DRM_I915_FBDEV=n
I.e. core fbdev is enabled and so we might load vesafb or efifb and similar firmware fbdev drivers. But drm/i915 fbdev emulation isn't enabled. Still we absolutely must kick off these firmware fbs in that case. -Daniel
Archit
Anyway current patch unfortunately won't work since we really must remove other framebuffers even in the FB=y, I915_FBDEV=n case. So I dropped it from drm-misc for now. Unfortunately that means all the driver conversions won't apply anymore either :(
Thanks, Daniel
static int setcolreg(struct drm_crtc *crtc, u16 red, u16 green, u16 blue, u16 regno, struct fb_info *info) { diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h index ef32500..cbdc69d 100644 --- a/include/drm/drm_fb_helper.h +++ b/include/drm/drm_fb_helper.h @@ -168,6 +168,10 @@ void drm_fb_helper_cfb_imageblit(struct fb_info *info,
void drm_fb_helper_set_suspend(struct drm_fb_helper *fb_helper, int state);
+int drm_fb_helper_remove_conflicting_framebuffers(struct apertures_struct *a,
const char *name,bool primary);int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info);
int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper);
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