Re: Warnings in DRM code when removing/unbinding a driver

[John Garry]

Hi Thomas,

> drm-tip now contains

I have tested today's linux-next, which includes this:

> commit a88248506a2bcfeaef6837a53cde19fe11970e6c
> Author: Thomas Zimmermann <tzimmermann@xxxxxxx>
> Date:   Tue Dec 3 09:38:15 2019 +0100
>
>      drm/hisilicon/hibmc: Switch to generic fbdev emulation
>
> which removes this entire code and switches hibmc to generic fbdev
> emulation. Does that fix the problem?

And I see no warn, here's a dmesg snippet:

[   20.672787] pci 0007:90:00.0: can't derive routing for PCI INT A
[   20.678831] hibmc-drm 0007:91:00.0: PCI INT A: no GSI
[   20.686536] pci_bus 0007:90: 2-byte config write to 0007:90:00.0 
offset 0x4 may corrupt adjacent RW1C bits
[   20.696888] [TTM] Zone  kernel: Available graphics memory: 57359458 KiB
[   20.703545] [TTM] Zone   dma32: Available graphics memory: 2097152 KiB
[   20.710108] [TTM] Initializing pool allocator
[   20.714561] [TTM] Initializing DMA pool allocator
[   20.720212] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[   20.726863] [drm] No driver support for vblank timestamp query.
[   20.754777] Console: switching to colour frame buffer device 100x37
[   20.778180] hibmc-drm 0007:91:00.0: fb0: hibmcdrmfb frame buffer device
[   20.786447] [drm] Initialized hibmc 1.0.0 20160828 for 0007:91:00.0 
on minor 0
[   20.794346] Console: switching to colour dummy device 80x25
[   20.801884] pci 0007:90:00.0: can't derive routing for PCI INT A
[   20.807963] hibmc-drm 0007:91:00.0: PCI INT A: no GSI
[   20.813656] [TTM] Finalizing pool allocator
[   20.817905] [TTM] Finalizing DMA pool allocator
[   20.822576] [TTM] Zone  kernel: Used memory at exit: 0 KiB
[   20.828760] [TTM] Zone   dma32: Used memory at exit: 0 KiB
[   20.834978] pci 0007:90:00.0: can't derive routing for PCI INT A
[   20.841021] hibmc-drm 0007:91:00.0: PCI INT A: no GSI
[   20.848858] [TTM] Zone  kernel: Available graphics memory: 57359458 KiB
[   20.855516] [TTM] Zone   dma32: Available graphics memory: 2097152 KiB
[   20.862079] [TTM] Initializing pool allocator
[   20.866525] [TTM] Initializing DMA pool allocator
[   20.872064] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[   20.878716] [drm] No driver support for vblank timestamp query.
[   20.905996] Console: switching to colour frame buffer device 100x37
[   20.929385] hibmc-drm 0007:91:00.0: fb0: hibmcdrmfb frame buffer device
[   20.937241] [drm] Initialized hibmc 1.0.0 20160828 for 0007:91:00.0 
on minor 0
[   21.171906] loop: module loaded

Thanks,
John

> Best regards
> Thomas
>
> > [ÂÂ 27.965802]Â hibmc_unload+0x2c/0xd0
> > [ÂÂ 27.969281]Â hibmc_pci_remove+0x2c/0x40
> > [ÂÂ 27.973109]Â pci_device_remove+0x6c/0x140
> > [ÂÂ 27.977110]Â really_probe+0x174/0x548
> > [ÂÂ 27.980763]Â driver_probe_device+0x7c/0x148
> > [ÂÂ 27.984936]Â device_driver_attach+0x94/0xa0
> > [ÂÂ 27.989109]Â __driver_attach+0xa8/0x110
> > [ÂÂ 27.992935]Â bus_for_each_dev+0xe8/0x158
> > [ÂÂ 27.996849]Â driver_attach+0x30/0x40
> > [ÂÂ 28.000415]Â bus_add_driver+0x234/0x2f0
> > [ÂÂ 28.004241]Â driver_register+0xbc/0x1d0
> > [ÂÂ 28.008067]Â __pci_register_driver+0xbc/0xd0
> > [ÂÂ 28.012329]Â hibmc_pci_driver_init+0x20/0x28
> > [ÂÂ 28.016590]Â do_one_initcall+0xb4/0x254
> > [ÂÂ 28.020417]Â kernel_init_freeable+0x27c/0x328
> > [ÂÂ 28.024765]Â kernel_init+0x10/0x118
> > [ÂÂ 28.028245]Â ret_from_fork+0x10/0x18
> > [ÂÂ 28.031813] ---[ end trace 35a83b71b657878d ]---
> > [ÂÂ 28.036503] ------------[ cut here ]------------
> > [ÂÂ 28.041115] WARNING: CPU: 24 PID: 1 at
> > drivers/gpu/drm/drm_gem_vram_helper.c:40
> > ttm_buffer_object_destroy+0x4c/0x80
> > [ÂÂ 28.051537] Modules linked in:
> > [ÂÂ 28.054585] CPU: 24 PID: 1 Comm: swapper/0 Tainted: GÂÂÂ BÂÂ W
> >  Â5.5.0-rc1-dirty #565
> > [ÂÂ 28.062924] Hardware name: Huawei D06 /D06, BIOS Hisilicon D06 UEFI
> > RC0 - V1.16.01 03/15/2019
> >
> > [snip]
> >
> > Indeed, simply unbinding the device from the driver causes the same sort
> > of issue:
> >
> > root@(none)$ cd ./bus/pci/drivers/hibmc-drm/
> > root@(none)$ ls
> > 0000:05:00.0Â bindÂÂÂÂÂÂÂÂÂ new_idÂÂÂÂÂÂÂ remove_idÂÂÂÂ uevent
> > unbind
> > root@(none)$ echo 0000\:05\:00.0 > unbind
> > [Â 116.074352] ------------[ cut here ]------------
> > [Â 116.078978] WARNING: CPU: 17 PID: 1178 at
> > drivers/gpu/drm/drm_gem_vram_helper.c:40
> > ttm_buffer_object_destroy+0x4c/0x80
> > [Â 116.089661] Modules linked in:
> > [Â 116.092711] CPU: 17 PID: 1178 Comm: sh Tainted: GÂÂÂ BÂÂ W
> > 5.5.0-rc1-dirty #565
> > [Â 116.100704] Hardware name: Huawei D06 /D06, BIOS Hisilicon D06 UEFI
> > RC0 - V1.16.01 03/15/2019
> > [Â 116.109218] pstate: 20400009 (nzCv daif +PAN -UAO)
> > [Â 116.114001] pc : ttm_buffer_object_destroy+0x4c/0x80
> > [Â 116.118956] lr : ttm_buffer_object_destroy+0x18/0x80
> > [Â 116.123910] sp : ffff0022e6cef8e0
> > [Â 116.127215] x29: ffff0022e6cef8e0 x28: ffff00231b1fb000
> > [Â 116.132519] x27: 0000000000000000 x26: ffff00231b1fb000
> > [Â 116.137821] x25: ffff0022e6cefdc0 x24: 0000000000002480
> > [Â 116.143124] x23: ffff0023682b6ab0 x22: ffff0023682b6800
> > [Â 116.148427] x21: ffff0023682b6800 x20: 0000000000000000
> > [Â 116.153730] x19: ffff0023682b6800 x18: 0000000000000000
> > [Â 116.159032] x17: 000000000000000000000000001
> > [Â 116.185545] x7 : ffff0023682b6b07 x6 : ffff80046d056d61
> > [Â 116.190848] x5 : ffff80046d056d61 x4 : ffff0023682b6ba0
> > [Â 116.196151] x3 : ffffa00010197338 x2 : dfffa00000000000
> > [Â 116.201453] x1 : 0000000000000003 x0 : 0000000000000001
> > [Â 116.206756] Call trace:
> > [Â 116.209195]Â ttm_buffer_object_destroy+0x4c/0x80
> > [Â 116.213803]Â ttm_bo_release_list+0x184/0x220
> > [Â 116.218064]Â ttm_bo_put+0x410/0x5d0
> > [Â 116.221544]Â drm_gem_vram_object_free+0xc/0x18
> > [Â 116.225979]Â drm_gem_object_free+0x34/0xd0
> > [Â 116.230066]Â drm_gem_object_put_unlocked+0xc8/0xf0
> > [Â 116.234848]Â hibmc_user_framebuffer_destroy+0x20/0x40
> > [Â 116.239890]Â drm_framebuffer_free+0x48/0x58
> > [Â 116.244064]Â drm_mode_object_put.part.1+0x90/0xe8
> > [Â 116.248759]Â drm_mode_object_put+0x28/0x38
> > [Â 116.252846]Â hibmc_fbdev_fini+0x54/0x78
> > [Â 116.256672]Â hibmc_unload+0x2c/0xd0
> > [Â 116.260151]Â hibmc_pci_remove+0x2c/0x40
> > [Â 116.263979]Â pci_device_remove+0x6c/0x140
> > [Â 116.267980]Â device_release_driver_internal+0x134/0x250
> > [Â 116.273196]Â device_driver_detach+0x28/0x38
> > [Â 116.277369]Â unbind_store+0xfc/0x150
> > [Â 116.280934]Â drv_attr_store+0x48/0x60
> > [Â 116.284589]Â sysfs_kf_write+0x80/0xb0
> > [Â 116.288241]Â kernfs_fop_write+0x1d4/0x320
> > [Â 116.292243]Â __vfs_write+0x54/0x98
> > [Â 116.295635]Â vfs_write+0xe8/0x270
> > [Â 116.298940]Â ksys_write+0xc8/0x180
> > [Â 116.302333]Â __arm64_sys_write+0x40/0x50
> > [Â 116.306248]Â el0_svc_common.constprop.0+0xa4/0x1f8
> > [Â 116.311029]Â el0_svc_handler+0x34/0xb0
> > [Â 116.314770]Â el0_sync_handler+0x10c/0x1c8
> > [Â 116.318769]Â el0_sync+0x140/0x180
> > [Â 116.322074] ---[ end trace e60e43d0e316b5c8 ]---
> > [Â 116.326868] ------------[ cut here ]------------
> >
> >
> > dmesg and .config is here:
> > https://pastebin.com/4P5yaZBS
> >
> > I'm not sure if this is a HIBMC driver issue or issue with the framework.
> >
> > john
> >
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@xxxxxxxxxxxxxxxxxxxxx
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel