On Mon, Jun 15, 2026 at 11:07:36PM +0300, Petre Rodan wrote:
> On Mon, Jun 15, 2026 at 02:09:13PM +1000, Jonathan Gray wrote:
> > On Sun, Jun 14, 2026 at 09:52:53PM +0300, Petre Rodan wrote:
> > > 9:0:0: ATI Navi 21
> > > 0x0000: Vendor ID: 1002, Product ID: 73bf
> > > 0x0004: Command: 0006, Status: 0010
> > > 0x0008: Class: 03 Display, Subclass: 00 VGA,
> > > Interface: 00, Revision: c3
> > > 0x000c: BIST: 00, Header Type: 80, Latency Timer: 00,
> > > Cache Line Size: 10
> > > 0x0010: BAR mem prefetchable 64bit addr: 0x0000007800000000/0x400000000
> > > 0x0018: BAR mem prefetchable 64bit addr: 0x0000007c00000000/0x10000000
> > > 0x0020: BAR io addr: 0x0000e000/0x0100
> > > 0x0024: BAR mem 32bit addr: 0xfca00000/0x00100000
> >
> > framebuffer memory is described by pci bar 0x10
> >
> > the window size here is already 16GB, even without resizing the bar
> >
> > can you try this diff to force visible vram to 512MB?
> >
> > Index: sys/dev/pci/drm/amd/amdgpu/amdgpu_gmc.c
> > ===================================================================
> > RCS file: /cvs/src/sys/dev/pci/drm/amd/amdgpu/amdgpu_gmc.c,v
> > diff -u -p -r1.20 amdgpu_gmc.c
> > --- sys/dev/pci/drm/amd/amdgpu/amdgpu_gmc.c 25 May 2026 08:56:32 -0000
> > 1.20
> > +++ sys/dev/pci/drm/amd/amdgpu/amdgpu_gmc.c 15 Jun 2026 03:53:34 -0000
> > @@ -216,6 +216,8 @@ void amdgpu_gmc_vram_location(struct amd
> > uint64_t vis_limit = (uint64_t)amdgpu_vis_vram_limit << 20;
> > uint64_t limit = (uint64_t)amdgpu_vram_limit << 20;
> >
> > + vis_limit = 512ULL << 20;
> > +
> > mc->vram_start = base;
> > mc->vram_end = mc->vram_start + mc->mc_vram_size - 1;
> > if (limit < mc->real_vram_size)
>
> I compared the amdgpu driver behaviour in OpenBSD vs Linux kernel 6.18.35 and
> to me it looks like the errors start at this bsd specific #ifdef block:
>
> RCS file: /cvs/src/sys/dev/pci/drm/amd/amdgpu/amdgpu_ttm.c,v
> diff -u -p -r1.30 amdgpu_ttm.c
> --- amdgpu_ttm.c 9 Mar 2026 23:57:53 -0000 1.30
> +++ amdgpu_ttm.c 15 Jun 2026 19:00:39 -0000
> @@ -2022,x +2022,y @@ int amdgpu_ttm_init(struct amdgpu_device
> #else
> if (bus_space_map(adev->memt, adev->gmc.aper_base,
> adev->gmc.visible_vram_size,
> BUS_SPACE_MAP_LINEAR | BUS_SPACE_MAP_PREFETCHABLE,
> &adev->mman.aper_bsh)) {
> adev->mman.aper_base_kaddr = NULL;
> + printf("~~~ explicit NULL, visible_vram_size 0x%llX\n",
> adev->gmc.visible_vram_size);
> } else {
> adev->mman.aper_base_kaddr = bus_space_vaddr(adev->memt,
> adev->mman.aper_bsh);
> + printf("~~~ aper_base_kaddr %p, visible_vram_size 0x%llX\n",
> adev->mman.aper_base_kaddr,
> + adev->gmc.visible_vram_size);
> }
> #endif
>
> <TLDR>
> in OpenBSD if bus_space_map() is true then aper_base_kaddr is explicitly
> NULLed out,
> and for some reason this happens if visible_vram_size > 2GB.
> in Linux aper_base_kaddr is a non-NULL pointer in all my tests.
> </TLDR>
>
> # in OpenBSD with vis_limit between 512-2048MB, startx is happy to use the
> modsetting driver:
>
> VRAM: 16368M 0x0000008000000000 - 0x00000083FEFFFFFF (16368M used)
> GART: 512M 0x0000000000000000 - 0x000000001FFFFFFF
> ~~~ aper_base_kaddr 0xffff8000699ea000, visible_vram_size 0x80000000
> amdgpu0: SIENNA_CICHLID GC 10.3.0 60 CU rev 0x01
> amdgpu0: 1920x1080, 32bpp
> wsdisplay0 at amdgpu0 mux 1
>
>
> # in OpenBSD with vis_limit >= 2560UL<<20, aper_base_kaddr is explicitly set
> to NULL and the init failure chain happens:
>
> VRAM: 16368M 0x0000008000000000 - 0x00000083FEFFFFFF (16368M used)
> GART: 512M 0x0000000000000000 - 0x000000001FFFFFFF
> ~~~ explicit NULL, visible_vram_size 0xA0000000
> [drm] *ERROR* v11 visible_vram_size a0000000 or aper_base_kaddr 0x0 is not
> initialized.
> drm:pid0:psp_sw_init *ERROR* Failed to process memory training!
>
> drm:pid0:amdgpu_device_ip_init *ERROR* sw_init of IP block <psp> failed -22
> drm:pid0:amdgpu_device_init *ERROR* amdgpu_device_ip_init failed
> drm:pid0:amdgpu_driver_load_kms *ERROR* Fatal error during GPU init
> WARNING !amdgpu_irq_enabled(adev, src, type) failed at
> /sys/dev/pci/drm/amd/amdgpu/amdgpu_irq.c:650
>
>
> # in linux, even with the default unlimited vis_limit, aper_base_kaddr does
> not get NULLed out:
>
> [ 8.101797] amdgpu 0000:09:00.0: amdgpu: VRAM: 16368M 0x0000008000000000 -
> 0x00000083FEFFFFFF (16368M used)
> [ 8.101799] amdgpu 0000:09:00.0: amdgpu: GART: 512M 0x0000000000000000 -
> 0x000000001FFFFFFF
> [ 8.101809] [drm] Detected VRAM RAM=16368M, BAR=16384M
> [ 8.101810] [drm] RAM width 256bits GDDR6
> [ 8.101908] amdgpu: ~~~ aper_base_kaddr 00000000dbe1887b,
> visible_vram_size 0x3FF000000
> [ 8.101937] amdgpu 0000:09:00.0: amdgpu: amdgpu: 16368M of VRAM memory
> ready
> [ 8.101939] amdgpu 0000:09:00.0: amdgpu: amdgpu: 16002M of GTT memory
> ready.
>
> am I getting warmer?
My 8GB Vega 56 shows up with a 256M window so I can't test on hardware.
Can you try the below diff and report back the dmesg changes?
33:0:0: ATI Radeon Rx Vega
0x0000: Vendor ID: 1002, Product ID: 687f
0x0004: Command: 0007, Status: 0010
0x0008: Class: 03 Display, Subclass: 00 VGA,
Interface: 00, Revision: c3
0x000c: BIST: 00, Header Type: 80, Latency Timer: 00,
Cache Line Size: 10
0x0010: BAR mem prefetchable 64bit addr: 0x00000000e0000000/0x10000000
0x0018: BAR mem prefetchable 64bit addr: 0x00000000f0000000/0x00200000
0x0020: BAR io addr: 0x0000e000/0x0100
0x0024: BAR mem 32bit addr: 0xfcb00000/0x00080000
Index: sys/dev/pci/drm/amd/amdgpu/amdgpu_drv.c
===================================================================
RCS file: /cvs/src/sys/dev/pci/drm/amd/amdgpu/amdgpu_drv.c,v
diff -u -p -r1.73 amdgpu_drv.c
--- sys/dev/pci/drm/amd/amdgpu/amdgpu_drv.c 15 Jun 2026 02:46:12 -0000
1.73
+++ sys/dev/pci/drm/amd/amdgpu/amdgpu_drv.c 16 Jun 2026 05:29:53 -0000
@@ -3409,6 +3409,8 @@ amdgpu_attach(struct device *parent, str
printf(": can't get framebuffer info\n");
return;
}
+printf("\n%s pci_mapreg_info fb_aper_offset 0x%lx fb_aper_size 0x%lx\n",
+ __func__, adev->fb_aper_offset, adev->fb_aper_size);
if (adev->fb_aper_offset == 0) {
bus_size_t start, end, pci_mem_end;
@@ -3432,6 +3434,8 @@ amdgpu_attach(struct device *parent, str
pci_conf_write(pa->pa_pc, pa->pa_tag,
AMDGPU_PCI_MEM + 4, (uint64_t)base >> 32);
adev->fb_aper_offset = base;
+printf("\n%s fallback fb_aper_offset 0x%lx fb_aper_size 0x%lx\n",
+ __func__, adev->fb_aper_offset, adev->fb_aper_size);
}
if (adev->family >= CHIP_BONAIRE)
Index: sys/arch/amd64/amd64/bus_space.c
===================================================================
RCS file: /cvs/src/sys/arch/amd64/amd64/bus_space.c,v
diff -u -p -r1.31 bus_space.c
--- sys/arch/amd64/amd64/bus_space.c 4 Jun 2026 05:22:04 -0000 1.31
+++ sys/arch/amd64/amd64/bus_space.c 16 Jun 2026 05:45:39 -0000
@@ -381,8 +381,10 @@ bus_space_map(bus_space_tag_t t, bus_add
*/
error = extent_alloc_region(ex, bpa, size,
EX_NOWAIT | (ioport_malloc_safe ? EX_MALLOCOK : 0));
- if (error)
+ if (error) {
+printf("\n%s extent_alloc_region error %d\n", __func__, error);
return (error);
+ }
/*
* For I/O space, that's all she wrote.
@@ -414,6 +416,7 @@ bus_space_map(bus_space_tag_t t, bus_add
bpa, size);
printf("bus_space_map: can't free region\n");
}
+printf("\n%s x86_mem_add_mapping error %d\n", __func__, error);
}
return (error);
@@ -522,8 +525,10 @@ x86_mem_add_mapping(bus_addr_t bpa, bus_
map_size = endpa - pa;
va = (vaddr_t)km_alloc(map_size, &kv_any, &kp_none, &kd_nowait);
- if (va == 0)
+ if (va == 0) {
+printf("\n%s km_alloc ENOMEM\n", __func__);
return (ENOMEM);
+ }
*bshp = (bus_space_handle_t)(va + (bpa & PGOFSET));
