From 7ac6269968826f9cad61b501bb613cc5cadb7229 Mon Sep 17 00:00:00 2001 From: Jagan Teki Date: Thu, 3 Oct 2019 12:15:21 +0530 Subject: [PATCH] drm/sun4i: dsi: Fix TCON DRQ set bits The LCD timing definitions between Linux DRM vs Allwinner are different, below diagram shows this clear differences. Active Front Sync Back Region Porch Porch <-----------------------><----------------><--------------><--------------> //////////////////////| ////////////////////// | ////////////////////// |.................. ................ ________________ <----- [hv]display -----> <------------- [hv]sync_start ------------> <--------------------- [hv]sync_end ----------------------> <-------------------------------- [hv]total ------------------------------> <----- lcd_[xy] --------> <- lcd_[hv]spw -> <---------- lcd_[hv]bp ---------> <-------------------------------- lcd_[hv]t ------------------------------> The DSI driver misinterpreted the hbp term from the BSP code to refer only to the backporch, when in fact it was backporch + sync. Thus the driver incorrectly used the horizontal front porch plus sync in its calculation of the DRQ set bit value, when it should not have included the sync timing. Including additional sync timings leads to 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-20190514-00026-g01f0c75b902d-dirty #13 Hardware name: Allwinner sun8i Family Workqueue: events deferred_probe_work_func [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (dump_stack+0x84/0x98) [] (dump_stack) from [] (__warn+0xfc/0x114) [] (__warn) from [] (warn_slowpath_fmt+0x44/0x68) [] (warn_slowpath_fmt) from [] (drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0) [] (drm_atomic_helper_wait_for_vblanks.part.1) from [] (drm_atomic_helper_commit_tail_rpm+0x5c/0x6c) [] (drm_atomic_helper_commit_tail_rpm) from [] (commit_tail+0x40/0x6c) [] (commit_tail) from [] (drm_atomic_helper_commit+0xbc/0x128) [] (drm_atomic_helper_commit) from [] (restore_fbdev_mode_atomic+0x1cc/0x1dc) [] (restore_fbdev_mode_atomic) from [] (drm_fb_helper_restore_fbdev_mode_unlocked+0x54/0xa0) [] (drm_fb_helper_restore_fbdev_mode_unlocked) from [] (drm_fb_helper_set_par+0x30/0x54) [] (drm_fb_helper_set_par) from [] (fbcon_init+0x560/0x5ac) [] (fbcon_init) from [] (visual_init+0xbc/0x104) [] (visual_init) from [] (do_bind_con_driver+0x1b0/0x390) [] (do_bind_con_driver) from [] (do_take_over_console+0x13c/0x1c4) [] (do_take_over_console) from [] (do_fbcon_takeover+0x74/0xcc) [] (do_fbcon_takeover) from [] (notifier_call_chain+0x44/0x84) [] (notifier_call_chain) from [] (__blocking_notifier_call_chain+0x48/0x60) [] (__blocking_notifier_call_chain) from [] (blocking_notifier_call_chain+0x18/0x20) [] (blocking_notifier_call_chain) from [] (register_framebuffer+0x1e0/0x2f8) [] (register_framebuffer) from [] (__drm_fb_helper_initial_config_and_unlock+0x2fc/0x50c) [] (__drm_fb_helper_initial_config_and_unlock) from [] (drm_fbdev_client_hotplug+0xe8/0x1b8) [] (drm_fbdev_client_hotplug) from [] (drm_fbdev_generic_setup+0x88/0x118) [] (drm_fbdev_generic_setup) from [] (sun4i_drv_bind+0x128/0x160) [] (sun4i_drv_bind) from [] (try_to_bring_up_master+0x164/0x1a0) [] (try_to_bring_up_master) from [] (__component_add+0x94/0x140) [] (__component_add) from [] (sun6i_dsi_probe+0x144/0x234) [] (sun6i_dsi_probe) from [] (platform_drv_probe+0x48/0x9c) [] (platform_drv_probe) from [] (really_probe+0x1dc/0x2c8) [] (really_probe) from [] (driver_probe_device+0x60/0x160) [] (driver_probe_device) from [] (bus_for_each_drv+0x74/0xb8) [] (bus_for_each_drv) from [] (__device_attach+0xd0/0x13c) [] (__device_attach) from [] (bus_probe_device+0x84/0x8c) [] (bus_probe_device) from [] (deferred_probe_work_func+0x64/0x90) [] (deferred_probe_work_func) from [] (process_one_work+0x204/0x420) [] (process_one_work) from [] (worker_thread+0x274/0x5a0) [] (worker_thread) from [] (kthread+0x11c/0x14c) [] (kthread) from [] (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 b57eb1e5c64c6b8b ]--- 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 With the terms(as described in above diagram) fixed, the panel displays correctly without any timeouts. Tested-by: Merlijn Wajer Signed-off-by: Jagan Teki Signed-off-by: Maxime Ripard Link: https://patchwork.freedesktop.org/patch/msgid/20191003064527.15128-2-jagan@amarulasolutions.com --- drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c index 1f63234b6346..5d9ad4654a1d 100644 --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c @@ -438,9 +438,9 @@ static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi, SUN6I_DSI_BURST_LINE_SYNC_POINT(SUN6I_DSI_SYNC_POINT)); val = SUN6I_DSI_TCON_DRQ_ENABLE_MODE; - } else if ((mode->hsync_end - mode->hdisplay) > 20) { + } else if ((mode->hsync_start - mode->hdisplay) > 20) { /* Maaaaaagic */ - u16 drq = (mode->hsync_end - mode->hdisplay) - 20; + u16 drq = (mode->hsync_start - mode->hdisplay) - 20; drq *= mipi_dsi_pixel_format_to_bpp(device->format); drq /= 32;