On Fri, Jun 21, 2019 at 2:05 PM Chen-Yu Tsai [off-list ref] wrote:

On Fri, May 24, 2019 at 6:27 PM Jagan Teki [off-list ref] wrote:

quoted

On Fri, May 24, 2019 at 2:18 AM Maxime Ripard [off-list ref] wrote:

quoted

On Mon, May 20, 2019 at 02:33:10PM +0530, Jagan Teki wrote:

quoted

The current code is computing vertical video start delay as

delay = mode->vtotal - (mode->vsync_end - mode->vdisplay) + start;

On which the second parameter

mode->vsync_end - mode->vdisplay = front porch + sync timings

according to "DRM kernel-internal display mode structure" in
include/drm/drm_modes.h

With adding additional sync timings, the desired video start delay
value as 510 for "bananapi,s070wv20-ct16" panel timings which indeed
trigger panel flip_done timed out as:

 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 Not tainted 5.1.0-next-20190514-00029-g09e5b0ed0a58 #18
 Hardware name: Allwinner sun8i Family
 Workqueue: events deferred_probe_work_func
 [<c010ed54>] (unwind_backtrace) from [<c010b76c>] (show_stack+0x10/0x14)
 [<c010b76c>] (show_stack) from [<c0688c70>] (dump_stack+0x84/0x98)
 [<c0688c70>] (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 [<c04156f8>] (drm_fb_helper_restore_fbdev_mode_unlocked+0x54/0xa0)
 [<c04156f8>] (drm_fb_helper_restore_fbdev_mode_unlocked) from [<c0415774>] (drm_fb_helper_set_par+0x30/0x54)
 [<c0415774>] (drm_fb_helper_set_par) from [<c03ad450>] (fbcon_init+0x560/0x5ac)
 [<c03ad450>] (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 [<c044b598>] (try_to_bring_up_master+0x164/0x1a0)
 [<c044b598>] (try_to_bring_up_master) from [<c044b668>] (__component_add+0x94/0x140)
 [<c044b668>] (__component_add) from [<c0445e1c>] (sun6i_dsi_probe+0x144/0x234)
 [<c0445e1c>] (sun6i_dsi_probe) from [<c0452ef4>] (platform_drv_probe+0x48/0x9c)
 [<c0452ef4>] (platform_drv_probe) from [<c04512cc>] (really_probe+0x1dc/0x2c8)
 [<c04512cc>] (really_probe) from [<c0451518>] (driver_probe_device+0x60/0x160)
 [<c0451518>] (driver_probe_device) from [<c044f7a4>] (bus_for_each_drv+0x74/0xb8)
 [<c044f7a4>] (bus_for_each_drv) from [<c045107c>] (__device_attach+0xd0/0x13c)
 [<c045107c>] (__device_attach) from [<c0450474>] (bus_probe_device+0x84/0x8c)
 [<c0450474>] (bus_probe_device) from [<c0450900>] (deferred_probe_work_func+0x64/0x90)
 [<c0450900>] (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 495200a78b24980e ]---
 random: fast init done
 [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

But the expected video start delay value is 513 which states that
the second parameter on the computation is "front porch" value
(no sync timings included).

This is clearly confirmed from the legacy [1] and new [2] bsp codes
that the second parameter on the video start delay is "front porch"

Here is the detailed evidence for calculating front porch as per
bsp code.

vfp = panel->lcd_vt - panel->lcd_y - panel->lcd_vbp
=> (panel->lcd_vt) - panel->lcd_y - panel->lcd_vbp
=> (tt->ver_front_porch + lcdp->panel_info.lcd_vbp
    + lcdp->panel_info.lcd_y) -  panel->lcd_y - panel->lcd_vbp
=> tt->ver_front_porch

The comment on patch 1 still applies on this patch

Thanks, I have responded on that. Same applies here.

So this patch fixes the misinterpretation of Allwinner's back porch value,
much like patch 1, but this one is for the vertical back porch. So I think
you should follow the same advice I gave you for patch 1.

Yes, indeed I'm planning to do the same. thanks!

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel