iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

drm/sun4i: backend: Make sure we don't have a commit pending

Browse Source 
If we try to read the backend registers while it fetches the new values, we
end up with the value of some random register instead of the one we asked
for.

In order to prevent that, let's make sure that the very first thing we do
during our atomic modesetting is to let the commit bit come to a rest.

We don't have to worry about anything else since the only time we will
trigger a new transaction is during the atomic_commit which comes much
later.

Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/35604307e5bde2b85c674de79fa7c4d55700f085.1516613040.git-series.maxime.ripard@free-electrons.com
This commit is contained in:
Maxime Ripard 2018-01-22 10:25:26 +01:00
parent 5d68be9185
commit dd63250c55
No known key found for this signature in database
GPG Key ID: D2B4C094214DAF74
1 changed files with 12 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/gpu/drm/sun4i/sun4i_backend.c
View File

@ -296,6 +296,17 @@ static bool sun4i_backend_plane_uses_frontend(struct drm_plane_state *state)
return sun4i_backend_plane_uses_scaler(state);
}
static void sun4i_backend_atomic_begin(struct sunxi_engine *engine,
struct drm_crtc_state *old_state)
{
u32 val;
WARN_ON(regmap_read_poll_timeout(engine->regs,
SUN4I_BACKEND_REGBUFFCTL_REG,
val, !(val & SUN4I_BACKEND_REGBUFFCTL_LOADCTL),
100, 50000));
}
static int sun4i_backend_atomic_check(struct sunxi_engine *engine,
struct drm_crtc_state *crtc_state)
{
@ -478,6 +489,7 @@ static struct sun4i_frontend *sun4i_backend_find_frontend(struct sun4i_drv *drv,
}
static const struct sunxi_engine_ops sun4i_backend_engine_ops = {
.atomic_begin = sun4i_backend_atomic_begin,
.atomic_check = sun4i_backend_atomic_check,
.commit = sun4i_backend_commit,
.layers_init = sun4i_layers_init,