Re: Bug 205201 - overflow of DMA mask and bus mask

[Christoph Hellwig]

On Tue, Nov 05, 2019 at 08:56:27AM +0100, Christian Zigotzky wrote:
> Hi All,
>
> We still have DMA problems with some PCI devices. Since the PowerPC updates 
> 4.21-1 [1] we need to decrease the RAM to 3500MB (mem=3500M) if we want to 
> work with our PCI devices. The FSL P5020 and P5040 have these problems 
> currently.
>
> Error message:
>
> [   25.654852] bttv 1000:04:05.0: overflow 0x00000000fe077000+4096 of DMA 
> mask ffffffff bus mask df000000
>
> All 5.x Linux kernels can't initialize a SCSI PCI card anymore so booting 
> of a Linux userland isn't possible.
>
> PLEASE check the DMA changes in the PowerPC updates 4.21-1 [1]. The kernel 
> 4.20 works with all PCI devices without limitation of RAM.

Can you send me the .config and a dmesg?  And in the meantime try the
patch below?

---