>-----Original Message----- >From: amd-gfx <amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of Deng, >Emily >Sent: Friday, December 21, 2018 5:41 PM >To: Michel Dänzer <michel@xxxxxxxxxxx> >Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx >Subject: RE: [PATCH] drm/amdgpu/virtual_dce: Need to pin the fb's bo > >>-----Original Message----- >>From: Michel Dänzer <michel@xxxxxxxxxxx> >>Sent: Friday, December 21, 2018 5:37 PM >>To: Deng, Emily <Emily.Deng@xxxxxxx> >>Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx >>Subject: Re: [PATCH] drm/amdgpu/virtual_dce: Need to pin the fb's bo >> >>On 2018-12-21 10:32 a.m., Deng, Emily wrote: >>>> -----Original Message----- >>>> From: Michel Dänzer <michel@xxxxxxxxxxx> >>>> Sent: Friday, December 21, 2018 5:28 PM >>>> To: Deng, Emily <Emily.Deng@xxxxxxx> >>>> Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx >>>> Subject: Re: [PATCH] drm/amdgpu/virtual_dce: Need to pin the fb's bo >>>> >>>> On 2018-12-21 10:17 a.m., Deng, Emily wrote: >>>>>> From: amd-gfx <amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of >>>>>> Deng, Emily >>>>>>> From: Michel Dänzer <michel@xxxxxxxxxxx> On 2018-12-21 9:45 a.m., >>>>>>> Deng, Emily wrote: >>>>>>>>> From: Michel Dänzer <michel@xxxxxxxxxxx> On 2018-12-21 8:26 >>>>>>>>> a.m., Emily Deng wrote: >>>>>>>>>> When the bo is used to set mode, the bo need to be pinned. >>>>>>>>> >>>>>>>>> On second thought, why does the BO need to be pinned? When >>>>>>>>> using the display hardware, the BO needs to be pinned to >>>>>>>>> prevent it from being moved while the hardware is scanning out >>>>>>>>> from it, but that shouldn't be >>>>>>> necessary here. >>>>>>>> The pin here is used for scan out the buffer by remote display app. >>>>>>> >>>>>>> I still don't understand why pinning is needed. What mechanism >>>>>>> does the remote display app use to access the BO contents? >>>>>> Sorry, I am not familiar with the remote display app. Maybe it >>>>>> will use drm ioctl function to get the current crtc's fb's >>>>>> information, and get the content in the fb's buffer object by mmap >>>>>> or translate the bo to an OpenGL texture for next rendering. Maybe >>>>>> don't need to pin the bo here, as the use has no different with other >normal bos. >>>>>> So please ignore the patch, and will send another patch to remove >>>>>> the unpin >>>> the fb's bo code. >>>>> It seems to be hard to remove all the pin for virtual_dce, as it >>>>> uses some >>>> common code in amdgpu_display.c. >>>> >>>> Because of amdgpu_display_unpin_work_func? That might be as simple >>>> as replacing >>>> >>>> schedule_work(&works->unpin_work); >>>> >>>> with >>>> >>>> kfree(works->shared); >>>> kfree(works); >>>> >>>> in dce_virtual_pageflip. >>> But the amdgpu_display_crtc_page_flip_target will pin the new_bo, >>> then we don't need to unpin it? >> >>Ah, right, but then dce_virtual_pageflip could just unpin it? Not >>ideal, but better than leaving it pinned unnecessarily. >Yes, it is not a good idea to leave it pinned. Then will need lots of "if >(amdgpu_virtual_display)", don't know whether it could be accept? Another method is let the logical stay no change, just use if (!amdgpu_virtual_display) before WARN_ON_ONCE of amdgpu_bo_unpin to remove the virtual_dce's call trace. Which method do you think is better? >> >> >>-- >>Earthling Michel Dänzer | http://www.amd.com >>Libre software enthusiast | Mesa and X developer >_______________________________________________ >amd-gfx mailing list >amd-gfx@xxxxxxxxxxxxxxxxxxxxx >https://lists.freedesktop.org/mailman/listinfo/amd-gfx _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
