On 9/2/2025 9:25 PM, Rob Clark wrote:
> On Tue, Sep 2, 2025 at 4:50 AM Akhil P Oommen <akhi...@oss.qualcomm.com>
> wrote:
>>
>> The drm_gem_for_each_gpuvm_bo() call from lookup_vma() accesses
>> drm_gem_obj.gpuva.list, which is not initialized when the drm driver
>> does not support DRIVER_GEM_GPUVA feature. Enable it for msm_kms
>> drm driver to fix the splat seen when msm.separate_gpu_drm=1 modparam
>> is set:
>>
>> [ 9.506020] Unable to handle kernel paging request at virtual address
>> fffffffffffffff0
>> [ 9.523160] Mem abort info:
>> [ 9.523161] ESR = 0x0000000096000006
>> [ 9.523163] EC = 0x25: DABT (current EL), IL = 32 bits
>> [ 9.523165] SET = 0, FnV = 0
>> [ 9.523166] EA = 0, S1PTW = 0
>> [ 9.523167] FSC = 0x06: level 2 translation fault
>> [ 9.523169] Data abort info:
>> [ 9.523170] ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000
>> [ 9.523171] CM = 0, WnR = 0, TnD = 0, TagAccess = 0
>> [ 9.523172] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
>> [ 9.523174] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000ad370f000
>> [ 9.523176] [fffffffffffffff0] pgd=0000000000000000,
>> p4d=0000000ad4787403, pud=0000000ad4788403, pmd=0000000000000000
>> [ 9.523184] Internal error: Oops: 0000000096000006 [#1] SMP
>> [ 9.592968] CPU: 9 UID: 0 PID: 448 Comm: (udev-worker) Not tainted
>> 6.17.0-rc4-assorted-fix-00005-g0e9bb53a2282-dirty #3 PREEMPT
>> [ 9.592970] Hardware name: Qualcomm CRD, BIOS
>> 6.0.240718.BOOT.MXF.2.4-00515-HAMOA-1 07/18/2024
>> [ 9.592971] pstate: a1400005 (NzCv daif +PAN -UAO -TCO +DIT -SSBS
>> BTYPE=--)
>> [ 9.592973] pc : lookup_vma+0x28/0xe0 [msm]
>> [ 9.592996] lr : get_vma_locked+0x2c/0x128 [msm]
>> [ 9.763632] sp : ffff800082dab460
>> [ 9.763666] Call trace:
>> [ 9.763668] lookup_vma+0x28/0xe0 [msm] (P)
>> [ 9.763688] get_vma_locked+0x2c/0x128 [msm]
>> [ 9.763706] msm_gem_get_and_pin_iova_range+0x68/0x11c [msm]
>> [ 9.763723] msm_gem_get_and_pin_iova+0x18/0x24 [msm]
>> [ 9.763740] msm_fbdev_driver_fbdev_probe+0xd0/0x258 [msm]
>> [ 9.763760] __drm_fb_helper_initial_config_and_unlock+0x288/0x528
>> [drm_kms_helper]
>> [ 9.763771] drm_fb_helper_initial_config+0x44/0x54 [drm_kms_helper]
>> [ 9.763779] drm_fbdev_client_hotplug+0x84/0xd4 [drm_client_lib]
>> [ 9.763782] drm_client_register+0x58/0x9c [drm]
>> [ 9.763806] drm_fbdev_client_setup+0xe8/0xcf0 [drm_client_lib]
>> [ 9.763809] drm_client_setup+0xb4/0xd8 [drm_client_lib]
>> [ 9.763811] msm_drm_kms_post_init+0x2c/0x3c [msm]
>> [ 9.763830] msm_drm_init+0x1a8/0x22c [msm]
>> [ 9.763848] msm_drm_bind+0x30/0x3c [msm]
>> [ 9.919273] try_to_bring_up_aggregate_device+0x168/0x1d4
>> [ 9.919283] __component_add+0xa4/0x170
>> [ 9.919286] component_add+0x14/0x20
>> [ 9.919288] msm_dp_display_probe_tail+0x4c/0xac [msm]
>> [ 9.919315] msm_dp_auxbus_done_probe+0x14/0x20 [msm]
>> [ 9.919335] dp_aux_ep_probe+0x4c/0xf0 [drm_dp_aux_bus]
>> [ 9.919341] really_probe+0xbc/0x298
>> [ 9.919345] __driver_probe_device+0x78/0x12c
>> [ 9.919348] driver_probe_device+0x40/0x160
>> [ 9.919350] __driver_attach+0x94/0x19c
>> [ 9.919353] bus_for_each_dev+0x74/0xd4
>> [ 9.919355] driver_attach+0x24/0x30
>> [ 9.919358] bus_add_driver+0xe4/0x208
>> [ 9.919360] driver_register+0x60/0x128
>> [ 9.919363] __dp_aux_dp_driver_register+0x24/0x30 [drm_dp_aux_bus]
>> [ 9.919365] atana33xc20_init+0x20/0x1000 [panel_samsung_atna33xc20]
>> [ 9.919370] do_one_initcall+0x6c/0x1b0
>> [ 9.919374] do_init_module+0x58/0x234
>> [ 9.919377] load_module+0x19cc/0x1bd4
>> [ 9.919380] init_module_from_file+0x84/0xc4
>> [ 9.919382] __arm64_sys_finit_module+0x1b8/0x2cc
>> [ 9.919384] invoke_syscall+0x48/0x110
>> [ 9.919389] el0_svc_common.constprop.0+0xc8/0xe8
>> [ 9.919393] do_el0_svc+0x20/0x2c
>> [ 9.919396] el0_svc+0x34/0xf0
>> [ 9.919401] el0t_64_sync_handler+0xa0/0xe4
>> [ 9.919403] el0t_64_sync+0x198/0x19c
>> [ 9.919407] Code: eb0000bf 54000480 d100a003 aa0303e2 (f8418c44)
>> [ 9.919410] ---[ end trace 0000000000000000 ]---
>>
>> Fixes: 217ed15bd399 ("drm/msm: enable separate binding of GPU and display
>> devices")
>> Signed-off-by: Akhil P Oommen <akhi...@oss.qualcomm.com>
>> ---
>> drivers/gpu/drm/msm/msm_drv.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
>> index
>> 9dcc7a596a11d9342a515dab694bac93dc2805cb..7e977fec4100792394dccf59097a01c2b2556608
>> 100644
>> --- a/drivers/gpu/drm/msm/msm_drv.c
>> +++ b/drivers/gpu/drm/msm/msm_drv.c
>> @@ -826,6 +826,7 @@ static const struct file_operations fops = {
>>
>> #define DRIVER_FEATURES_KMS ( \
>> DRIVER_GEM | \
>> + DRIVER_GEM_GPUVA | \
>
> Hmm, the description of DRIVER_GEM_GPUVA is that "Driver supports user
> defined GPU VA bindings for GEM objects", which isn't really true.
> Fortunately the only thing that it actually seems to control currently
> is the list head initialization.
>
> Idk if it would be better to make the list head init unconditional, or
> just add a comment here?
But the KMS-only drm driver do use symbols related to gpuva. "struct
gpuva" for eg:. From that perspective, shouldn't we select this feature
here?
-Akhil
>
> BR,
> -R
>
>> DRIVER_ATOMIC | \
>> DRIVER_MODESET | \
>> 0 )
>>
>> --
>> 2.50.1
>>
