tilcdc reliably hits warning in drm_atomic_helper_crtc_duplicate_state() on BeagleBone black

[Uwe Kleine-König]

Hello,

running a plain Debian 6.16 kernel on a BeagleBone black board (with
nothing connected to the graphics output) I reliably hit:

[   91.228190] tilcdc 4830e000.lcdc: no encoders/connectors found
[   91.343877] ------------[ cut here ]------------
[   91.348862] WARNING: CPU: 0 PID: 325 at drivers/gpu/drm/drm_atomic_state_helper.c:174 drm_atomic_helper_crtc_duplicate_state+0x68/0x70 [drm_kms_helper]
[   91.363362] Modules linked in: tilcdc(+) stp llc drm_dma_helper omap_aes_driver omap_sham drm_client_lib omap_crypto crypto_engine drm_kms_helper omap_rng ti_am335x_adc kfifo_buf tps65218_pwrbutton industrialio at24 leds_gpio cpufreq_dt binfmt_misc drm configfs nfnetlink ip_tables x_tables autofs4 ext4 mbcache jbd2 crc32c_cryptoapi smsc crc16 davinci_mdio mdio_bitbang mdio_devres ti_cpsw_new cpsw_common of_mdio fixed_phy fwnode_mdio libphy mdio_bus sdhci_omap omap_hwspinlock sdhci_pltfm musb_dsps sdhci musb_hdrc omap_wdt udc_core phy_gmii_sel phy_am335x usbcore ti_am335x_tscadc tps65217 phy_am335x_control cppi41 phy_generic
[   91.421946] CPU: 0 UID: 0 PID: 325 Comm: (udev-worker) Not tainted 6.16-armmp #1 NONE  Debian 6.16-1~exp1
[   91.421984] Hardware name: Generic AM33XX (Flattened Device Tree)
[   91.422000] Call trace:
[   91.422021]  unwind_backtrace from show_stack+0x18/0x1c
[   91.422100]  show_stack from dump_stack_lvl+0x54/0x68
[   91.422160]  dump_stack_lvl from __warn+0x88/0x11c
[   91.422213]  __warn from warn_slowpath_fmt+0x188/0x194
[   91.422253]  warn_slowpath_fmt from drm_atomic_helper_crtc_duplicate_state+0x68/0x70 [drm_kms_helper]
[   91.422390]  drm_atomic_helper_crtc_duplicate_state [drm_kms_helper] from drm_atomic_get_crtc_state+0x70/0x110 [drm]
[   91.422829]  drm_atomic_get_crtc_state [drm] from drm_atomic_helper_disable_all+0x98/0x1d0 [drm_kms_helper]
[   91.423080]  drm_atomic_helper_disable_all [drm_kms_helper] from drm_atomic_helper_shutdown+0x98/0x150 [drm_kms_helper]
[   91.423193]  drm_atomic_helper_shutdown [drm_kms_helper] from tilcdc_fini+0x58/0xd0 [tilcdc]
[   91.423376]  tilcdc_fini [tilcdc] from tilcdc_init.constprop.0+0x1dc/0x60c [tilcdc]
[   91.423498]  tilcdc_init.constprop.0 [tilcdc] from tilcdc_pdev_probe+0x58/0xac [tilcdc]
[   91.423613]  tilcdc_pdev_probe [tilcdc] from platform_probe+0x64/0xbc
[   91.423703]  platform_probe from really_probe+0xd8/0x3ac
[   91.423741]  really_probe from __driver_probe_device+0x94/0x1e0
[   91.423774]  __driver_probe_device from driver_probe_device+0x38/0xd4
[   91.423806]  driver_probe_device from __driver_attach+0xc0/0x1b8
[   91.423837]  __driver_attach from bus_for_each_dev+0x84/0xd4
[   91.423868]  bus_for_each_dev from bus_add_driver+0xf8/0x21c
[   91.423896]  bus_add_driver from driver_register+0x88/0x124
[   91.423927]  driver_register from do_one_initcall+0x50/0x258
[   91.423960]  do_one_initcall from do_init_module+0x5c/0x254
[   91.423993]  do_init_module from init_module_from_file+0x9c/0xec
[   91.424022]  init_module_from_file from sys_finit_module+0x1d0/0x334
[   91.424052]  sys_finit_module from __sys_trace_return+0x0/0x10
[   91.424081] Exception stack(0xe0141fa8 to 0xe0141ff0)
[   91.424108] 1fa0:                   b56b8d73 00000000 0000001c b56bde10 00000004 02240ea0
[   91.424133] 1fc0: b56b8d73 00000000 69828600 0000017b 022392c0 0223e780 00000000 00000000
[   91.424151] 1fe0: bef00618 bef00608 b56b96e9 b6b13312
[   91.638906] ---[ end trace 0000000000000000 ]---
[   91.643839] tilcdc 4830e000.lcdc: [drm] *ERROR* Disabling all crtc's during unload failed with -12

during late boot.

The problem seems to be old, because 6.12 emits a very similar warning.

I didn't try to debug that, but if you have things to test, I can
probably do that.

Best regards
Uwe
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 488 bytes
Desc: not available
URL: <https://lists.freedesktop.org/archives/dri-devel/attachments/20250806/8b96baf2/attachment.sig>