Re: [PATCH 6/7] drm/i915: fbdev_set_par reliably invalidating frontbuffer

Daniel Vetter
2015-07-08T09:41:44Z

On Tue, Jul 07, 2015 at 04:28:56PM -0700, Rodrigo Vivi wrote:
> fbdev_set_par is called when fbcon is taking over control, but
> frontbuffer was being invalidated only on the first time when
> moving obj to GTT domain.
> However on the following calls write domain was already GTT
> so invalidate was never called again.
>
> The issue was mainly on boot with plymouth doing a splash screen
> when returning to the console frontbuffer wans't being invalidated
> causing missed screen updates with PSR enabled.
>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> ---
> drivers/gpu/drm/i915/intel_fbdev.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
> index 2a1724e..a76cebc 100644
> --- a/drivers/gpu/drm/i915/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/intel_fbdev.c
> @@ -50,6 +50,7 @@ static int intel_fbdev_set_par(struct fb_info *info)
> struct drm_fb_helper *fb_helper = info->par;
> struct intel_fbdev *ifbdev =
> container_of(fb_helper, struct intel_fbdev, helper);
> + struct drm_i915_gem_object *obj = ifbdev->fb->obj;
> int ret;
>
> ret = drm_fb_helper_set_par(info);
> @@ -63,8 +64,13 @@ static int intel_fbdev_set_par(struct fb_info *info)
> * now until we solve this for real.
> */
> mutex_lock(&fb_helper->dev->struct_mutex);
> - ret = i915_gem_object_set_to_gtt_domain(ifbdev->fb->obj,
> - true);
> + if (obj) {
> + if (obj->base.write_domain != I915_GEM_DOMAIN_GTT)
> + ret = i915_gem_object_set_to_gtt_domain(obj,
> + true);
> + else
> + intel_fb_obj_invalidate(obj, ORIGIN_GTT);

Unconditional intel_fb_obj_invalidate is what we need here really. And for
reference maybe mention the commit that fixed this for the set_domain
ioctl:

commit 031b698a77a70a6c394568034437b5486a44e868
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Fri Jun 26 19:35:16 2015 +0200

drm/i915: Unconditionally do fb tracking invalidate in set_domain

> + }
> mutex_unlock(&fb_helper->dev->struct_mutex);
> }
>
> --
> 2.1.0
>
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--
Daniel Vetter
Software Engineer, Intel Corporation