start value in video start delay was changed in commit da676c6aa641 ("drm/sun4i: dsi: Change the start delay calculation") to match the legacy BSP driver [1].
So, using this existing start delay computation gives the wrong start delay value for the "bananapi,s070wv20-ct16" panel. Due to this the panel trigger below flip_done timed out as during kernel bootup:
WARNING: CPU: 0 PID: 31 at drivers/gpu/drm/drm_atomic_helper.c:1429 drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0 [CRTC:46:crtc-0] vblank wait timed out Modules linked in: CPU: 0 PID: 31 Comm: kworker/0:1 Tainted: G W 5.1.0-next-20190514-00025-gf928bc7cc146 #15 Hardware name: Allwinner sun8i Family Workqueue: events deferred_probe_work_func [<c010ed54>] (unwind_backtrace) from [<c010b76c>] (show_stack+0x10/0x14) [<c010b76c>] (show_stack) from [<c0688c90>] (dump_stack+0x84/0x98) [<c0688c90>] (dump_stack) from [<c011d9e4>] (__warn+0xfc/0x114) [<c011d9e4>] (__warn) from [<c011da40>] (warn_slowpath_fmt+0x44/0x68) [<c011da40>] (warn_slowpath_fmt) from [<c040cd50>] (drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0) [<c040cd50>] (drm_atomic_helper_wait_for_vblanks.part.1) from [<c040e694>] (drm_atomic_helper_commit_tail_rpm+0x5c/0x6c) [<c040e694>] (drm_atomic_helper_commit_tail_rpm) from [<c040e4dc>] (commit_tail+0x40/0x6c) [<c040e4dc>] (commit_tail) from [<c040e5cc>] (drm_atomic_helper_commit+0xbc/0x128) [<c040e5cc>] (drm_atomic_helper_commit) from [<c0411b64>] (restore_fbdev_mode_atomic+0x1cc/0x1dc) [<c0411b64>] (restore_fbdev_mode_atomic) from [<c0411cb0>] (drm_fb_helper_pan_display+0xac/0x1d0) [<c0411cb0>] (drm_fb_helper_pan_display) from [<c03a4e84>] (fb_pan_display+0xcc/0x134) [<c03a4e84>] (fb_pan_display) from [<c03b1214>] (bit_update_start+0x14/0x30) [<c03b1214>] (bit_update_start) from [<c03afe94>] (fbcon_switch+0x3d8/0x4e0) [<c03afe94>] (fbcon_switch) from [<c03ec930>] (redraw_screen+0x174/0x238) [<c03ec930>] (redraw_screen) from [<c03aceb4>] (fbcon_prepare_logo+0x3c4/0x400) [<c03aceb4>] (fbcon_prepare_logo) from [<c03ad2b8>] (fbcon_init+0x3c8/0x5ac) [<c03ad2b8>] (fbcon_init) from [<c03eb8a0>] (visual_init+0xbc/0x104) [<c03eb8a0>] (visual_init) from [<c03ed1b8>] (do_bind_con_driver+0x1b0/0x390) [<c03ed1b8>] (do_bind_con_driver) from [<c03ed780>] (do_take_over_console+0x13c/0x1c4) [<c03ed780>] (do_take_over_console) from [<c03ad800>] (do_fbcon_takeover+0x74/0xcc) [<c03ad800>] (do_fbcon_takeover) from [<c013c9c8>] (notifier_call_chain+0x44/0x84) [<c013c9c8>] (notifier_call_chain) from [<c013cd20>] (__blocking_notifier_call_chain+0x48/0x60) [<c013cd20>] (__blocking_notifier_call_chain) from [<c013cd50>] (blocking_notifier_call_chain+0x18/0x20) [<c013cd50>] (blocking_notifier_call_chain) from [<c03a6e44>] (register_framebuffer+0x1e0/0x2f8) [<c03a6e44>] (register_framebuffer) from [<c04153c0>] (__drm_fb_helper_initial_config_and_unlock+0x2fc/0x50c) [<c04153c0>] (__drm_fb_helper_initial_config_and_unlock) from [<c04158c8>] (drm_fbdev_client_hotplug+0xe8/0x1b8) [<c04158c8>] (drm_fbdev_client_hotplug) from [<c0415a20>] (drm_fbdev_generic_setup+0x88/0x118) [<c0415a20>] (drm_fbdev_generic_setup) from [<c043f060>] (sun4i_drv_bind+0x128/0x160) [<c043f060>] (sun4i_drv_bind) from [<c044b5b0>] (try_to_bring_up_master+0x164/0x1a0) [<c044b5b0>] (try_to_bring_up_master) from [<c044b680>] (__component_add+0x94/0x140) [<c044b680>] (__component_add) from [<c0445e1c>] (sun6i_dsi_probe+0x144/0x234) [<c0445e1c>] (sun6i_dsi_probe) from [<c0452f0c>] (platform_drv_probe+0x48/0x9c) [<c0452f0c>] (platform_drv_probe) from [<c04512e4>] (really_probe+0x1dc/0x2c8) [<c04512e4>] (really_probe) from [<c0451530>] (driver_probe_device+0x60/0x160) [<c0451530>] (driver_probe_device) from [<c044f7bc>] (bus_for_each_drv+0x74/0xb8) [<c044f7bc>] (bus_for_each_drv) from [<c0451094>] (__device_attach+0xd0/0x13c) [<c0451094>] (__device_attach) from [<c045048c>] (bus_probe_device+0x84/0x8c) [<c045048c>] (bus_probe_device) from [<c0450918>] (deferred_probe_work_func+0x64/0x90) [<c0450918>] (deferred_probe_work_func) from [<c0135970>] (process_one_work+0x204/0x420) [<c0135970>] (process_one_work) from [<c013690c>] (worker_thread+0x274/0x5a0) [<c013690c>] (worker_thread) from [<c013b3d8>] (kthread+0x11c/0x14c) [<c013b3d8>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c) Exception stack(0xde539fb0 to 0xde539ff8) 9fa0: 00000000 00000000 00000000 00000000 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 ---[ end trace 755e10f62b83f396 ]--- Console: switching to colour frame buffer device 100x30 [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CRTC:46:crtc-0] flip_done timed out [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CONNECTOR:48:DSI-1] flip_done timed out [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [PLANE:30:plane-0] flip_done timed out
To fix this, adjust the start delay computation according to the new BSP code [2].
Unfortunately we don't have any evidence or documentation for this reassignment to 1 in new bsp, but it is working with below mainline supported panels in A33, A64. - bananapi,s070wv20-ct16 - feiyang,fy07024di26a30d - techstar,ts8550b
So, use the start as per new bsp code since it is working in all the supported panels.
[1] https://github.com/BPI-SINOVOIP/BPI-M2M-bsp/blob/master/linux-sunxi/drivers/... [2] https://github.com/BPI-SINOVOIP/BPI-M2M-bsp/blob/master/linux-sunxi/drivers/...
Signed-off-by: Jagan Teki jagan@amarulasolutions.com --- drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c index f83522717488..c9c99c52bf1e 100644 --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c @@ -365,7 +365,17 @@ static void sun6i_dsi_inst_init(struct sun6i_dsi *dsi, static u16 sun6i_dsi_get_video_start_delay(struct sun6i_dsi *dsi, struct drm_display_mode *mode) { - u16 start = clamp(mode->vtotal - mode->vdisplay - 10, 8, 100); + /** + * Allwinner legacy (drivers/video/sunxi/legacy), + * new (drivers/video/sunxi/disp/de/lowlevel_sun8iw5) bsp drivers + * are evaluating start as: + * + * vtotal - vdisplay - 10 + * + * but the new drivers are reassigning start to 1, which seems to be + * working in DSI panels available in mainline. + */ + u8 start = 1; u16 delay = mode->vtotal - (mode->vsync_end - mode->vdisplay) + start;
if (delay > mode->vtotal)