On 10/02/2014 08:52 PM, Andrzej Hajda wrote:
Hi,
+CC possible victims
On 10/02/2014 12:52 PM, Inki Dae wrote:
On 2014년 10월 02일 17:58, Joonyoung Shim wrote:
Hi Andrzej,
On 10/01/2014 05:14 PM, Andrzej Hajda wrote:
The patch disables vblanks during dpms off only if pagefilp has
not been finished. It also replaces drm_vblank_off with drm_crtc_vblank_put.
It fixes issue with page_flip ioctl not being able to acquire vblank counter.
This problem isn't related with pageflip, it just causes from
7ffd7a68511c710b84db3548a1997fd2625f580a commit (drm: Always reject
drm_vblank_get() after drm_vblank_off()).
We need to use drm_vblank_on() as a counterpart to drm_vblank_off()
after the commit .
This patch should break also other drivers, it seems at least following
drms could be affected:
armada, sti, tegra.
Indeed we (tegra) have just been hit by this. The problem seems to come
from the fact that we have been using drm_vblank_pre_modeset,
drm_vblank_post_modeset and drm_vblank_off conjointly. All these
functions depend on the value of vblank->inmodeset, and 7ffd7a68511
increases the vblank reference counter only in drm_vblank_off, which can
result in the acquired reference never being released.
The following seems to fix this for Tegra, by stopping using
drm_vblank_pre/post_modeset and relying on drm_vblank_off/on instead:
diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index b08df07cad47..3955d81236d0 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -739,7 +739,6 @@ static const struct drm_crtc_funcs tegra_crtc_funcs = {
static void tegra_crtc_disable(struct drm_crtc *crtc)
{
- struct tegra_dc *dc = to_tegra_dc(crtc);
struct drm_device *drm = crtc->dev;
struct drm_plane *plane;
@@ -755,7 +754,7 @@ static void tegra_crtc_disable(struct drm_crtc *crtc)
}
}
- drm_vblank_off(drm, dc->pipe);
+ drm_crtc_vblank_off(crtc);
}
static bool tegra_crtc_mode_fixup(struct drm_crtc *crtc,
@@ -844,7 +843,7 @@ static int tegra_crtc_mode_set(struct drm_crtc *crtc,
u32 value;
int err;
- drm_vblank_pre_modeset(crtc->dev, dc->pipe);
+ drm_crtc_vblank_off(crtc);
err = tegra_crtc_setup_clk(crtc, mode);
if (err) {
@@ -946,7 +945,7 @@ static void tegra_crtc_commit(struct drm_crtc *crtc)
value = GENERAL_ACT_REQ | WIN_A_ACT_REQ;
tegra_dc_writel(dc, value, DC_CMD_STATE_CONTROL);
- drm_vblank_post_modeset(crtc->dev, dc->pipe);
+ drm_crtc_vblank_on(crtc);
}
static void tegra_crtc_load_lut(struct drm_crtc *crtc)
Thierry, does this look ok to you?
But there might be another issue, which is that calls to
drm_vblank_get() will return -EINVAL if invoked between drm_blank_off
and drm_blank_on. Is this really the desired behavior? Can it at least
happen? If so, how are drivers supposed to react to this situation?
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