[PATCH 0/2] Provide init/release functions for struct ttm_bo_global

Thomas Zimmermann tzimmermann at suse.de
Thu Aug 30 10:35:45 UTC 2018


Am 30.08.2018 um 08:45 schrieb Christian König:
[...]
>> or create their private instance.
> 
> That doesn't sounds good. Drivers should not be allowed to create their
> own private instance of that.

OK, will be changed in the patchset.

Best regards
Thomas

> 
> Thanks for doing this,
> Christian.
> 
>>   It's also a step towards drm device
>> hotplug, which someone just asked.
>>
>> Best regards
>> Thomas
>>
>>
>> Am 13.08.2018 um 12:33 schrieb Christian König:
>>> Yes, please! I had it on my TODO list to clean that up for an eternity.
>>>
>>> Actually I never understood why that should be driver work to setup TTM?
>>>
>>> I mean can't we just have a module_init/module_exit for TTM?
>>>
>>> Thanks,
>>> Christian.
>>>
>>> Am 13.08.2018 um 12:24 schrieb Thomas Zimmermann:
>>>> TTM uses global memory and BO for backing graphics buffers. These are
>>>> represented by struct ttm_mem_global and struct ttm_bo_global.
>>>>
>>>> Currently, struct ttm_bo_global can only be initialized and released
>>>> through
>>>> struct ttm_bo_global_ref. This is a workaround for passing an
>>>> instance of
>>>> ttm_mem_global to the BO global initialization code.
>>>>
>>>> The use of struct ttm_bo_global_ref makes driver code unnecessary
>>>> hard to
>>>> understand. At the same time drivers can use any combination of memory
>>>> and
>>>> BO for initializing the global instances. This can result in subtle
>>>> bugs
>>>> when the order of initializing and releasing drivers changes.
>>>>
>>>> As a first step for resolving these problems, the provided patch set
>>>> separates initialization and release of struct ttm_bo_global from
>>>> struct ttm_bo_global_ref.
>>>>
>>>> The first patch only renames ttm_bo_global_{init/release}. Hopefully
>>>> this
>>>> change can be applied at once for all drivers.
>>>>
>>>> Future directions: All TTM-based drivers follow the same pattern for
>>>> setting
>>>> up the TTM. In a follow-up patch, this code can be moved into a single
>>>> place
>>>> and shared among drivers.
>>>>
>>>> Thomas Zimmermann (2):
>>>>     drm/ttm: Rename ttm_bo_global_{init,release}() to
>>>>       ttm_bo_global_ref_*()
>>>>     drm/ttm: Provide ttm_bo_global_{init/release}() for struct
>>>>       ttm_bo_global
>>>>
>>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c     |  4 +-
>>>>    drivers/gpu/drm/ast/ast_ttm.c               |  4 +-
>>>>    drivers/gpu/drm/bochs/bochs_mm.c            |  4 +-
>>>>    drivers/gpu/drm/cirrus/cirrus_ttm.c         |  4 +-
>>>>    drivers/gpu/drm/hisilicon/hibmc/hibmc_ttm.c |  4 +-
>>>>    drivers/gpu/drm/mgag200/mgag200_ttm.c       |  4 +-
>>>>    drivers/gpu/drm/nouveau/nouveau_ttm.c       |  4 +-
>>>>    drivers/gpu/drm/qxl/qxl_ttm.c               |  4 +-
>>>>    drivers/gpu/drm/radeon/radeon_ttm.c         |  4 +-
>>>>    drivers/gpu/drm/ttm/ttm_bo.c                | 12 ++---
>>>>    drivers/gpu/drm/virtio/virtgpu_ttm.c        |  4 +-
>>>>    drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c    |  4 +-
>>>>    drivers/staging/vboxvideo/vbox_ttm.c        |  4 +-
>>>>    include/drm/ttm/ttm_bo_driver.h             | 53
>>>> ++++++++++++++++-----
>>>>    14 files changed, 70 insertions(+), 43 deletions(-)
>>>>
>>>> -- 
>>>> 2.18.0
>>>>
> 
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-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Linux GmbH, Maxfeldstr. 5, D-90409 Nürnberg
Tel: +49-911-74053-0; Fax: +49-911-7417755;  https://www.suse.com/
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard,
Graham Norton, HRB 21284 (AG Nürnberg)

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