<html> <head> <meta content="text/html; charset=utf-8" http-equiv="Content-Type"> </head> <body bgcolor="#FFFFFF" text="#000000"> <div class="moz-cite-prefix">On 2015年11月10日 23:01, Liviu Dudau wrote: </div> <blockquote cite="mid:20151110150102.GP963@e106497-lin.cambridge.arm.com" type="cite"> <pre wrap="">Hello, When booting my Juno board with the HDLCD driver that I have converted to atomic operations I'm getting the following warning: ------------[ cut here ]------------ WARNING: at /work/repositories/kernel/drivers/gpu/drm/drm_atomic_helper.c:674 Modules linked in: hdlcd(+) clk_scpi CPU: 3 PID: 1375 Comm: systemd-udevd Not tainted 4.3.0-next-20151109+ #5 Hardware name: ARM Juno development board (r0) (DT) task: ffffffc974888b00 ti: ffffffc9755dc000 task.ti: ffffffc9755dc000 PC is at drm_atomic_helper_update_legacy_modeset_state+0x204/0x20c LR is at drm_atomic_helper_commit_modeset_disables+0x1c0/0x394 pc : [<ffffffc0003e6d18>] lr : [<ffffffc0003e8214>] pstate: 20000145 sp : ffffffc9755df430 x29: ffffffc9755df430 x28: ffffffc975703600 x27: 0000000000000000 x26: ffffffc976253960 x25: ffffffc976254040 x24: ffffffc000819000 x23: ffffffc000689ea0 x22: ffffffc976251800 x21: ffffffc976251800 x20: 0000000000000000 x19: ffffffc9766b1f80 x18: 00000000715fe015 x17: 0000007fb4b855b0 x16: 0000000000000220 x15: 0000000000000001 x14: 0ffffffffffffffe x13: 0000000000000008 x12: 0101010101010101 x11: ffffffc000964000 x10: ffffffc0009d2000 x9 : 0000000000000000 x8 : ffffffc97ff5f700 x7 : ffffffc97566cb80 x6 : ffffffc9766b1700 x5 : ffffffc975665100 x4 : 0000000000000000 x3 : ffffffc976253960 x2 : ffffffc97566cd00 x1 : ffffffc976253900 x0 : 0000000000000000 ---[ end trace 9fe289f798e7178e ]--- Call trace: [<ffffffc0003e6d18>] drm_atomic_helper_update_legacy_modeset_state+0x204/0x20c [<ffffffc0003e8214>] drm_atomic_helper_commit_modeset_disables+0x1c0/0x394 [<ffffffc0003e84c8>] drm_atomic_helper_commit+0xe0/0x150 [<ffffffc00040bcc0>] drm_atomic_commit+0x40/0x6c [<ffffffc0003e92c0>] restore_fbdev_mode+0x294/0x2d4 [<ffffffc0003eb6ec>] drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x8c [<ffffffc0003eb770>] drm_fb_helper_set_par+0x2c/0x58 [<ffffffc000378048>] fbcon_init+0x4d4/0x534 [<ffffffc0003b44f4>] visual_init+0xac/0x104 [<ffffffc0003b63f8>] do_bind_con_driver+0x16c/0x398 [<ffffffc0003b6968>] do_take_over_console+0xd8/0x1f4 [<ffffffc00037811c>] do_fbcon_takeover+0x74/0xf8 [<ffffffc00037c5cc>] fbcon_event_notify+0x8a4/0x8f8 [<ffffffc0000d19f0>] notifier_call_chain+0x4c/0x88 [<ffffffc0000d1d78>] __blocking_notifier_call_chain+0x44/0x74 [<ffffffc0000d1dbc>] blocking_notifier_call_chain+0x14/0x1c [<ffffffc00037d614>] fb_notifier_call_chain+0x1c/0x24 [<ffffffc00037f8a8>] register_framebuffer+0x1c0/0x2ac [<ffffffc0003eb9f8>] drm_fb_helper_initial_config+0x25c/0x3ec [<ffffffc0003ec28c>] drm_fbdev_cma_init+0x98/0x134 [<ffffffbffc006780>] hdlcd_drm_bind+0x180/0x498 [hdlcd] [<ffffffc0004158e0>] try_to_bring_up_master.part.5+0xd4/0x118 [<ffffffc0004159e8>] component_master_add_with_match+0xc4/0x148 [<ffffffc000415a7c>] component_master_add+0x10/0x18 [<ffffffbffc0065ec>] hdlcd_probe+0x14/0x28 [hdlcd] [<ffffffc00041c504>] platform_drv_probe+0x54/0xc0 [<ffffffc00041a9b0>] driver_probe_device+0x1ec/0x2e8 [<ffffffc00041ab48>] __driver_attach+0x9c/0xa0 [<ffffffc000418bcc>] bus_for_each_dev+0x58/0x98 [<ffffffc00041a41c>] driver_attach+0x20/0x28 [<ffffffc00041a058>] bus_add_driver+0x1c8/0x22c [<ffffffc00041b3d0>] driver_register+0x68/0x108 [<ffffffc00041c408>] __platform_driver_register+0x4c/0x54 [<ffffffbffc00b018>] hdlcd_init+0x18/0x30 [hdlcd] [<ffffffc00008293c>] do_one_initcall+0x90/0x1a8 [<ffffffc0001424dc>] do_init_module+0x60/0x1c8 [<ffffffc00011d364>] load_module+0x1554/0x1c98 [<ffffffc00011dc64>] SyS_finit_module+0x7c/0x88 [<ffffffc000085cb0>] el0_svc_naked+0x24/0x28 The line that triggers the warning is: 674: WARN_ON(!connector->encoder->crtc); As far as I can see the encoder->crtc value is being set to a non-NULL value only in two places: - in drm_atomic_helper_update_legacy_modeset_state() after WARN_ON() encoder->crtc = connector->state->crtc; - in drm_crtc_helper_set_config(drm_mode_set *set): encoder->crtc = new_crtc; Nothing in the call path from drm_atomic_commit() calls crtc_funcs->set_config() or drm_crtc_helper_set_config() directly, so the question is if this WARN() is actually valid. Call path from drm_atomic_commit: drm_atomic_helper_commit() - drm_atomic_helper_prepare_planes() - drm_atomic_helper_swap_state() - drm_atomic_helper_commit_modeset_disables() - disable_outputs() - drm_atomic_helper_update_legacy_modeset_state() - WARN_ON(!connector->encoder->crtc) Best regards, Liviu </pre> </blockquote> Hi Liviu <meta http-equiv="content-type" content="text/html; charset=utf-8"> I solved this problem by following change, you can check if your driver do the same things: drivers/gpu/drm/bridge/dw_hdmi.c: - hdmi->connector.encoder = encoder; +// hdmi->connector.encoder = encoder; drm_mode_connector_attach_encoder(&hdmi->connector, encoder); I found some other drivers set connector.encoder before drm_mode_connector_attach_encoder, some are not. drm_mode_connector_attach_encoder already describe the link of connector and encoder, so I think "connector.encoder = encoder" is not needed, is that right? Thanks. <pre class="moz-signature" cols="72">-- Ｍark Yao</pre> </body> </html>