Hi Geert,
Thanks for your bug report.
The issue looks to be related to the nested V4L2 async notifiers. I
tried to recreate the DT setup on M3-N but failed to trigger the issue.
I will try to get hold of an Ebisu board and try to trigger the issue
and get back to you.
On 2022-06-08 12:16:48 +0200, Geert Uytterhoeven wrote:
> Hi Niklas,
>
> On Mon, Jan 24, 2022 at 8:13 PM Niklas Söderlund
> <niklas.soderlund+renesas@xxxxxxxxxxxx> wrote:
> > When Gen3 support was first added to this R-Car VIN and CSI-2 driver the
> > routing was centred around the CHSEL register which multiplexes the
> > different parallel buses that sit between the CSI-2 receivers source
> > side and the VIN dma engines. This was a bad design as the multiplexing
> > do allow for only a few combinations and do not play nice with many
> > video streams in the system.
> >
> > For example it's only possible for CSI-2 Virtual Channels 0 and 1 of any
> > given CSI-2 receiver to be used together with the scaler.
> >
> > Later datasheets have expanded the documentation and it is now possible
> > to improve on this design by allowing any Virtual Channel to be routed
> > to any R-Car VIN instance, provided that there exists a parallel bus
> > between them. This increases the flexibility as all Virtual Channels can
> > now be used together with the scaler for example.
> >
> > The redesign is not however perfect. While the new design allows for
> > many more routes, two constrains limit a small portion of routes that
> > was possible in the old design but are no more.
> >
> > - It is no longer possible to route the same CSI-2 and VC to more then
> > one VIN at a time. This was theoretically possible before if the
> > specific SoC allowed for the same CSI-2 and VC to be routed to two
> > different VIN capture groups.
> >
> > - It is no longer possible to simultaneously mix links from two CSI-2 IP
> > blocks to the same VIN capture group.
> >
> > For example if VIN2 is capturing from CSI40 then VIN{0,1,3} must also
> > capture from CSI40. While VIN{4,5,6,7} is still free to capture from
> > any other CSI-2 IP in the system. Once all VIN{0,1,2,3} links to CSI40
> > are disabled that VIN capture group is free again to capture from any
> > other CSI-2 IP it is connected to.
> >
> > At the core of the redesign is greater cooperator of the R-Car VIN and
> > CSI-2 drivers in configuring the routing. The VIN driver is after this
> > change only responsible to configure the full VIN capture groups
> > parallel buses to be to a particular CSI-2 IP. While the configuration
> > of which CSI-2 Virtual Channel is outputted on which of the R-Car CSI-2
> > IP output ports is handled by the CSI-2 driver.
> >
> > Before this change the CSI-2 Virtual Channel to output port was static
> > in the CSI-2 driver and the different links only manipulated the VIN
> > capture groups CHSEL register. With this change both the CHSEl register
> > and the CSI-2 routing VCDT registers are modified for greater
> > flexibility.
> >
> > This change touches both the R-Car VIN and R-Car CSI-2 drivers in the
> > same commit as both drivers cooperate closely and one change without the
> > other would more or less break video capture.
> >
> > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
> > Tested-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
>
> Thanks for your patch, which is now commit 3e52419ec04f9769 ("media:
> rcar-{csi2,vin}: Move to full Virtual Channel routing per CSI-2 IP")
> in v5.18-rc1.
>
> This patch causes, depending on probe order, either one of the two
> failures below (with some debug info added) on Ebisu-4D (but not
> on Salvator-X(S)):
>
> 1. rcar-vin: probe of e6ef5000.video failed with error -22
>
> Probing e6500000.i2c
> Probing adv748x
> adv748x 0-0070: Endpoint
> /soc/i2c@e6500000/video-receiver@70/ports/port@7/endpoint on port 7
> adv748x 0-0070: Endpoint
> /soc/i2c@e6500000/video-receiver@70/ports/port@8/endpoint on port 8
> adv748x 0-0070: Endpoint
> /soc/i2c@e6500000/video-receiver@70/ports/port@a/endpoint on port 10
> Probing feaa0000.csi2
> Probing e6ef4000.video
> rcar-csi2 feaa0000.csi2: Consider updating driver rcar-csi2
> to match on endpoints
> rcar-vin e6ef4000.video: Device registered as video0
> Probing e6ef5000.video
> rcar-vin e6ef5000.video: Device registered as video1
> rcar-vin e6ef4000.video: Removing video0
> rcar-vin e6ef5000.video: Removing video1
> rcar-vin e6ef5000.video: Notifier registration failed
> rcar-vin e6ef5000.video: rcar_vin_probe: rvin_csi2_init()
> returned -EINVAL
> rcar-vin: probe of e6ef5000.video failed with error -22
>
> This is seen with v5.18-rc1 and later, but somehow I never noticed before.
>
> 2. rcar-csi2: probe of feaa0000.csi2 failed with error -22
>
> Probing e6500000.i2c
> Probing adv748x
> adv748x 0-0070: Endpoint
> /soc/i2c@e6500000/video-receiver@70/ports/port@7/endpoint on port 7
> adv748x 0-0070: Endpoint
> /soc/i2c@e6500000/video-receiver@70/ports/port@8/endpoint on port 8
> adv748x 0-0070: Endpoint
> /soc/i2c@e6500000/video-receiver@70/ports/port@a/endpoint on port 10
> Probing feaa0000.csi2
> rcar-csi2 feaa0000.csi2: Consider updating driver rcar-csi2 to
> match on endpoints
> Probing e6ef4000
> rcar-vin e6ef4000.video: Device registered as video0
> Probing e6ef5000
> rcar-vin e6ef5000.video: Device registered as video1
> rcar-vin e6ef4000.video: Removing video0
> rcar-vin e6ef5000.video: Removing video1
> rcar-csi2 feaa0000.csi2: rcsi2_probe:
> v4l2_async_register_subdev() returned -EINVAL
> rcar-csi2: probe of feaa0000.csi2 failed with error -22
>
> This is seen with[1], and did draw my attention, as it causes
> a big splat later:
>
> [ OK ] Started D-Bus System Message Bus.
> Unable to handle kernel NULL pointer dereference at virtual
> address 0000000000000000
> Unable to handle kernel NULL pointer dereference at virtual
> address 0000000000000000
> Mem abort info:
> ESR = 0x0000000096000004
> Mem abort info:
> ESR = 0x0000000096000004
> EC = 0x25: DABT (current EL), IL = 32 bits
> SET = 0, FnV = 0
> EC = 0x25: DABT (current EL), IL = 32 bits
> EA = 0, S1PTW = 0
> FSC = 0x04: level 0 translation fault
> SET = 0, FnV = 0
> Data abort info:
> ISV = 0, ISS = 0x00000004
> EA = 0, S1PTW = 0
> FSC = 0x04: level 0 translation fault
> CM = 0, WnR = 0
> user pgtable: 4k pages, 48-bit VAs, pgdp=000000004ec45000
> [0000000000000000] pgd=0000000000000000, p4d=0000000000000000
> Data abort info:
> Internal error: Oops: 96000004 [#1] PREEMPT SMP
> CPU: 0 PID: 374 Comm: v4l_id Tainted: G W
> 5.19.0-rc1-arm64-renesas-00799-gc13c3e49e8bd #1660
> ISV = 0, ISS = 0x00000004
> Hardware name: Renesas Ebisu-4D board based on r8a77990 (DT)
> pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> CM = 0, WnR = 0
> pc : subdev_open+0x8c/0x128
> lr : subdev_open+0x78/0x128
> sp : ffff80000aadba60
> x29: ffff80000aadba60 x28: 0000000000000000 x27: ffff80000aadbc58
> x26: 0000000000020000 x25: ffff00000b3aaf00 x24: 0000000000000000
> x23: ffff00000c331c00 x22: ffff000009aa61b8 x21: ffff000009aa6000
> x20: ffff000008bae3e8 x19: ffff00000c3fe200 x18: 0000000000000000
> x17: ffff800076945000 x16: ffff800008004000 x15: 00008cc6bf550c7c
> x14: 000000000000038f x13: 000000000000001a x12: ffff00007fba8618
> x11: 0000000000000001 x10: 0000000000000000 x9 : ffff800009253954
> x8 : ffff00000b3aaf00 x7 : 0000000000000004 x6 : 000000000000001a
> x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000001
> x2 : 0000000100000001 x1 : 0000000000000000 x0 : 0000000000000000
> Call trace:
> subdev_open+0x8c/0x128
> v4l2_open+0xa4/0x120
> chrdev_open+0x78/0x178
> do_dentry_open+0xfc/0x398
> vfs_open+0x28/0x30
> path_openat+0x584/0x9c8
> do_filp_open+0x80/0x108
> do_sys_openat2+0x20c/0x2d8
> user pgtable: 4k pages, 48-bit VAs, pgdp=000000004ec53000
> do_sys_open+0x54/0xa0
> __arm64_sys_openat+0x20/0x28
> invoke_syscall+0x40/0xf8
> el0_svc_common.constprop.0+0xf0/0x110
> do_el0_svc+0x20/0x78
> el0_svc+0x48/0xd0
> el0t_64_sync_handler+0xb0/0xb8
> el0t_64_sync+0x148/0x14c
> Code: f9405280 f9400400 b40000e0 f9400280 (f9400000)
> ---[ end trace 0000000000000000 ]---
>
> Adding debug prints to subdev_open() shows the opened files are
> v4l-subdev1 and v4l-subdev2, which correspond to subdevs on
> /soc/e6500000.i2c/i2c-0/0-0070.
>
> Reverting this commit fixes the issue.
>
> [1] "[PATCH v2 0/9] deferred_probe_timeout logic clean up"
> https://lore.kernel.org/r/20220601070707.3946847-1-saravanak@xxxxxxxxxx
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
> -- Linus Torvalds
--
Kind Regards,
Niklas Söderlund
