On Tue, Jun 11, 2024 at 11:29:58AM +0200, Thomas Zimmermann wrote:
HiI think when you have an iommu dma_alloc just allocates pages, and uses
Am 11.06.24 um 10:23 schrieb Peng Fan:
So fbdev-dma would be correct. But with the gem-dma allocator, wouldn't youSubject: Re: [PATCH] drm/fbdev-dma: fix getting smem_startDRM_GEM_DMA_DRIVER_OPS
Hi
Am 11.06.24 um 03:00 schrieb Peng Fan:
Which DRM memory manager does that driver use?Subject: Re: [PATCH] drm/fbdev-dma: fix getting smem_startIt is NXP i.MX95 DPU driver which is still in NXP downstream repo.
Hi
Am 04.06.24 um 10:03 schrieb Peng Fan (OSS):
From: Peng Fan <peng.fan@xxxxxxx>there is dump below:
If 'info->screen_buffer' locates in vmalloc address space,
virt_to_page will not be able to get correct results. With
CONFIG_DEBUG_VM and CONFIG_DEBUG_VIRTUAL enabled on ARM64,
Which graphics driver triggers this bug?
allocate from one of these dma_alloc_() calls at [1] ? How does the drivers
end up with vmalloc'd fbdev memory? Specifically in the light of the docs at
[2].
the iommu to make it all contiguous for the device, and vmalloc for the
kernel. So it's not allocated with vmalloc(), just ends up getting mapped
into the vmalloc range.
-Sima
[1] https://elixir.bootlin.com/linux/v6.9/source/drivers/gpu/drm/drm_gem_dma_helper.c#L146
[2] https://elixir.bootlin.com/linux/v6.9/source/Documentation/core-api/dma-api-howto.rst#L124
Best regards
Thomas
--I'm asking because if the driver allocates BOs via vmalloc(), should it reallyWe use it for fbdev emulation. If drm_kms_helper.fbdev_emulation is 0,
use fbdev-dma?
fbdev emulation could be disabled.
Thanks
Peng
Best regards
Thomas
Thanks,--
Peng.
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman HRB
36809 (AG Nuernberg)
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)