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@xxxxxxxxxxxxxx> --- 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. 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); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation
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