Re: [PATCH v6 3/5] fbdev: Disable sysfb device registration when removing conflicting FBs

From: Zack Rusin
Date: Thu Jun 16 2022 - 17:04:01 EST


On Thu, 2022-06-16 at 21:55 +0200, Javier Martinez Canillas wrote:
> Hello Zack,
>
> On 6/16/22 21:29, Zack Rusin wrote:
> > On Tue, 2022-06-07 at 20:23 +0200, Javier Martinez Canillas wrote:
> > > The platform devices registered by sysfb match with firmware-based DRM or
> > > fbdev drivers, that are used to have early graphics using a framebuffer
> > > provided by the system firmware.
> > >
>
> [snip]
>
> >
> > Hi, Javier.
> >
> > This change broke arm64 with vmwgfx. We get a kernel oops at boot (let me know if
> > you'd like .config or just have us test something directly for you):
> >
>
> Yes please share your .config and I'll try to reproduce on an arm64 machine.

Attached. It might be a little hard to reproduce unless you have an arm64 machine
with a dedicated gpu. You'll need a system that actually transitions from a generic
fb driver (e.g. efifb) to the dedicated one.

> >
> > Unable to handle kernel NULL pointer dereference at virtual address
> > 0000000000000008
> > Mem abort info:
> > ESR = 0x96000004
> > EC = 0x25: DABT (current EL), IL = 32 bits
> > SET = 0, FnV = 0
> > EA = 0, S1PTW = 0
> > FSC = 0x04: level 0 translation fault
> > Data abort info:
> > ISV = 0, ISS = 0x00000004
> > CM = 0, WnR = 0
> > user pgtable: 4k pages, 48-bit VAs, pgdp=00000001787ee000
> > [0000000000000008] pgd=0000000000000000, p4d=0000000000000000
> > Internal error: Oops: 96000004 [#1] SMP
> > Modules linked in: vmwgfx(+) e1000e(+) nvme ahci(+) xhci_pci drm_ttm_helper ttm
> > sha256_arm64 sha1_ce nvme_core xhci_pci_renesas aes_neon_bs aes_neon_blk aes>
> > CPU: 3 PID: 215 Comm: systemd-udevd Tainted: G U 5.18.0-rc5-vmwgfx
> > #12
>
> I'm confused, your kernel version seems to be 5.18.0-rc5 but this patch
> is only in drm-misc-next now and will land in 5.20...
>
> Did you backport it? Can you please try to reproduce with latest drm-tip ?

No, this is drm-misc-next as of yesterday. drm-misc-next was still on 5.18.0-rc5
yesterday.

z

Attachment: arm64config.gz
Description: arm64config.gz