On Thu, Jun 13, 2024 at 12:18:55PM +0200, Thomas Zimmermann wrote:
HiYeah we'd always need to make this conditional on the memory not being in
Am 13.06.24 um 12:14 schrieb Thomas Zimmermann:
Hi
Am 12.06.24 um 17:00 schrieb Daniel Vetter:
On Wed, Jun 12, 2024 at 10:37:14AM +0200, Thomas Zimmermann wrote:Enabling CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM would still crash the NXP
Hi JavierWe could make it all conditional on CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM, and
Am 12.06.24 um 09:49 schrieb Javier Martinez Canillas:
Thomas Zimmermann <tzimmermann@xxxxxxx> writes:These smem_ fields are clearly designed for PCI BARs of
Hello Thomas,
HiAgreed.
Am 10.06.24 um 10:47 schrieb Thomas Zimmermann:
HiI'm taking back my r-b. The memory is expected to by be physically
Am 04.06.24 um 10:03 schrieb Peng Fan (OSS):
From: Peng Fan <peng.fan@xxxxxxx>Which graphics driver triggers this bug?
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, there is dump below:
[ 3.536043] ------------[ cut here ]------------Reviewed-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
[ 3.540716] virt_to_phys used for non-linear address:
000000007fc4f540 (0xffff800086001000)
[ 3.552628] WARNING: CPU: 4 PID: 61 at
arch/arm64/mm/physaddr.c:12
__virt_to_phys+0x68/0x98
[ 3.565455] Modules linked in:
[ 3.568525] CPU: 4 PID: 61 Comm: kworker/u12:5 Not tainted
6.6.23-06226-g4986cc3e1b75-dirty #250
[ 3.577310] Hardware name: NXP i.MX95 19X19 board (DT)
[ 3.582452] Workqueue: events_unbound deferred_probe_work_func
[ 3.588291] pstate: 60400009 (nZCv daif +PAN
-UAO -TCO -DIT -SSBS
BTYPE=--)
[ 3.595233] pc : __virt_to_phys+0x68/0x98
[ 3.599246] lr : __virt_to_phys+0x68/0x98
[ 3.603276] sp : ffff800083603990
[ 3.677939] Call trace:
[ 3.680393] __virt_to_phys+0x68/0x98
[ 3.684067] drm_fbdev_dma_helper_fb_probe+0x138/0x238
[ 3.689214]
__drm_fb_helper_initial_config_and_unlock+0x2b0/0x4c0
[ 3.695385] drm_fb_helper_initial_config+0x4c/0x68
[ 3.700264] drm_fbdev_dma_client_hotplug+0x8c/0xe0
[ 3.705161] drm_client_register+0x60/0xb0
[ 3.709269] drm_fbdev_dma_setup+0x94/0x148
So add a check 'is_vmalloc_addr'.
Fixes: b79fe9abd58b ("drm/fbdev-dma: Implement fbdev emulation for
GEM DMA helpers")
Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
contiguous and vmalloc() won't guarantee that.
traditional graphics
cards. So can we even assume contiguous memory for DMA? That was my
assumption, but with IOMMUs it might not be the case. Fbdev-dma
only sets
smem_start to support a single old userspace driver. Maybe we
should further
restrict usage of this field by making it opt-in for each driver. Best
regards Thomas
remove the FBINFO_HIDE_SMEM_START flag. The reason I've done the flag is
that with the old fb_mmap code we had to always fill out smem_start to
make mmap work. But now that the various drm fbdev helpers have all
their
own mmap implementation, we could make this a lot cleaner.
driver. I think I'll add a flag to drm_fbdev_dma_setup() to set
smem_start from within lima, which is the only driver that requires
it.I'd like to remove CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM and all that, but
I fear that it would break someone's setup. Best regards Thomas
the vmalloc range, or things will blow up.
I've been looking atThe mali driver here was the out-of-tree proprietary mali driver as the
https://lore.kernel.org/dri-devel/20240318-dark-mongoose-of-camouflage-7ac6ed@houat/
and I'm now confused to find that lima doesn't even set up fbdev support.
consumer of such buffers.
The "exporters" was just any random fbdev driver, and with the DRM option
to set the smem, also drm drivers could play in this role. It at least
seems to have helped a few people to move away from out-of-tree fbdev
drivers to upstream drm drivers (but still with the out-of-tree mali gpu
driver). Which means we've needed this for any display driver that
happens to have shipped together with one of these older mali gpus.
It's a bit a mess, and it might indeed have outlived it's usefulness.
Cheers, Sima