drm/imx: lock scanout transfers for consecutive bursts

[Patrick Brünn]

Hi Philipp,

since commit 790cb4c7c9545953d22d3d425e49b36a711bae5b my display on CX9020 (a i.MX53 based machine) stopped working:

 # dmesg | grep -i drm
[    0.141829] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[    0.141838] [drm] No driver support for vblank timestamp query.
[    0.142016] imx-drm display-subsystem: bound imx-ipuv3-crtc.2 (ops ipu_crtc_ops)
[    0.142114] imx-drm display-subsystem: bound imx-ipuv3-crtc.3 (ops ipu_crtc_ops)
[    0.142219] imx-drm display-subsystem: bound display-0 (ops imx_pd_ops)
[    0.167491] drm: XXXXX: num_bursts: 8
[    0.242633] imx-drm display-subsystem: fb0:  frame buffer device
[    0.243172] [drm] Initialized imx-drm 1.0.0 20120507 for display-subsystem on minor 0
[   11.366172] [drm:drm_atomic_helper_commit_cleanup_done] *ERROR* [CRTC:28:crtc-0] flip_done timed out
[   21.606164] [drm:drm_atomic_helper_commit_cleanup_done] *ERROR* [CRTC:28:crtc-0] flip_done timed out

When I remove the new call to ipu_idmac_lock_enable(ipu_plane->ipu_ch, num_bursts) (attached patch),
"[drm:drm_atomic_helper_commit_cleanup_done] *ERROR* [CRTC:28:crtc-0] flip_done timed out"
messages disappear and I get my display back:
# dmesg | grep -i drm
[    0.142292] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[    0.142302] [drm] No driver support for vblank timestamp query.
[    0.142484] imx-drm display-subsystem: bound imx-ipuv3-crtc.2 (ops ipu_crtc_ops)
[    0.142587] imx-drm display-subsystem: bound imx-ipuv3-crtc.3 (ops ipu_crtc_ops)
[    0.142693] imx-drm display-subsystem: bound display-0 (ops imx_pd_ops)
[    0.167917] drm: XXXXX: num_bursts: 8
[    0.243023] imx-drm display-subsystem: fb0:  frame buffer device
[    0.243566] [drm] Initialized imx-drm 1.0.0 20120507 for display-subsystem on minor 0

Is your patch supposed to work on i.MX53, too? Did I miss some configuration [1], to make it work correctly?
If you need any additional info, just let me know.

Best Regards,
Patrick

[1] http://elixir.free-electrons.com/linux/v4.14-rc4/source/arch/arm/boot/dts/imx53-cx9020.dts#L29

---
 drivers/gpu/drm/imx/ipuv3-plane.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/imx/ipuv3-plane.c b/drivers/gpu/drm/imx/ipuv3-plane.c
index cf98596c7ce1..ca9513a09cfc 100644
--- a/drivers/gpu/drm/imx/ipuv3-plane.c
+++ b/drivers/gpu/drm/imx/ipuv3-plane.c
@@ -610,7 +610,7 @@ static void ipu_plane_atomic_update(struct drm_plane *plane,
        info = drm_format_info(fb->format->format);
        ipu_calculate_bursts(width, info->cpp[0], fb->pitches[0],
                             &burstsize, &num_bursts);
-
+printk("drm: XXXXX: num_bursts: %u\n", num_bursts);
        ipu_cpmem_zero(ipu_plane->ipu_ch);
        ipu_cpmem_set_resolution(ipu_plane->ipu_ch, width, height);
        ipu_cpmem_set_fmt(ipu_plane->ipu_ch, fb->format->format);
@@ -685,7 +685,7 @@ static void ipu_plane_atomic_update(struct drm_plane *plane,
        }
        ipu_cpmem_set_buffer(ipu_plane->ipu_ch, 0, eba);
        ipu_cpmem_set_buffer(ipu_plane->ipu_ch, 1, eba);
-       ipu_idmac_lock_enable(ipu_plane->ipu_ch, num_bursts);
+//XXX  ipu_idmac_lock_enable(ipu_plane->ipu_ch, num_bursts);
        ipu_plane_enable(ipu_plane);
 }

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