From 42ef024d10bf3d5e453227de86d7b4609a574eb2 Mon Sep 17 00:00:00 2001 From: Rob Clark Date: Fri, 4 Mar 2022 12:21:45 -0800 Subject: [PATCH] drm/msm: Fix dirtyfb refcounting commit 6cf1ba54d6910472a4b8a663e61bee6f9ea5556f upstream. refcount_t complains about 0->1 transitions, which isn't *quite* what we wanted. So use dirtyfb==1 to mean that the fb is not connected to any output that requires dirtyfb flushing, so that we can keep the underflow and overflow checking. Fixes: ec882c8d0ec6 ("drm/msm: Avoid dirtyfb stalls on video mode displays (v2)") Signed-off-by: Rob Clark Link: https://lore.kernel.org/r/20220304202146.845566-1-robdclark@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/msm/msm_fb.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/msm/msm_fb.c b/drivers/gpu/drm/msm/msm_fb.c index 96b379a08327c..7137492fe78e2 100644 --- a/drivers/gpu/drm/msm/msm_fb.c +++ b/drivers/gpu/drm/msm/msm_fb.c @@ -37,7 +37,7 @@ static int msm_framebuffer_dirtyfb(struct drm_framebuffer *fb, /* If this fb is not used on any display requiring pixel data to be * flushed, then skip dirtyfb */ - if (refcount_read(&msm_fb->dirtyfb) == 0) + if (refcount_read(&msm_fb->dirtyfb) == 1) return 0; return drm_atomic_helper_dirtyfb(fb, file_priv, flags, color, @@ -221,6 +221,8 @@ static struct drm_framebuffer *msm_framebuffer_init(struct drm_device *dev, goto fail; } + refcount_set(&msm_fb->dirtyfb, 1); + drm_dbg_state(dev, "create: FB ID: %d (%p)", fb->base.id, fb); return fb; -- 2.39.5