Hi Skateman,Skateman wrote:Kernel 5.5 Alpha 6 up and running on the AmigaOne X5000
Many thanks for testing the alpha6!
Have a nice Sunday evening!
Code: Select all
Oops: Kernel access of bad area, sig: 11 [#1] .do_mount_root+0x4c/0x16c [unreliable]
Michael Ellerman wrote: On Wed, 2019-12-04 at 12:35:24 UTC, Mike Rapoport wrote:
> From: Mike Rapoport <email@example.com>
> Some powerpc platforms (e.g. 85xx) limit DMA-able memory way below 4G. If a
> system has more physical memory than this limit, the swiotlb buffer is not
> addressable because it is allocated from memblock using top-down mode.
> Force memblock to bottom-up mode before calling swiotlb_init() to ensure
> that the swiotlb buffer is DMA-able.
> Link: https://lkml.kernel.org/r/F1EBB706-73DF ... enosoft.de
> Reported-by: Christian Zigotzky <firstname.lastname@example.org>
> Signed-off-by: Mike Rapoport <email@example.com>
Applied to powerpc fixes, thanks.
https://git.kernel.org/powerpc/c/8fabc6 ... 86c1fa33af
We still have some issues with PCI cards in our FSL P5020 and P5040
systems since the DMA mapping updates. [1, 2]
We have to limit the RAM to 3500MB for some problematic PCI cards.
(kernel boot argument 'mem=3500M')
The problematic DMA mapping code was added with the PowerPC updates
4.21-1 to the official kernel source code last year. 
We have created a bug report. 
The old 4.x kernels aren't affected because they use the old DMA code.
Please check the new DMA code again.
http://forum.hyperion-entertainment.com ... 486#p49486
http://forum.hyperion-entertainment.com ... =50#p49099
https://git.kernel.org/pub/scm/linux/ke ... a1186c96e2
On 28 November 2018 at 4:55 pm, Christian Zigotzky wrote:
> On 28 November 2018 at 12:05PM, Michael Ellerman wrote:
>> Nothing specific yet.
>> I'm a bit worried it might break one of the many old obscure platforms
>> we have that aren't well tested.
> Please don't apply the new DMA mapping code if you don't be sure if it
> works on all supported PowerPC machines. Is the new DMA mapping code
> really necessary? It's not really nice, to rewrote code if the old
> code works perfect. We must not forget, that we work for the end
> users. Does the end user have advantages with this new code? Is it
> faster? The old code works without any problems. I am also worried
> about this code. How can I test this new DMA mapping code?