Am 22.01.19 um 20:34 schrieb Tristan Bastian:
Thierry Reding – Tue, 22. January 2019 17:13
On Tue, Jan 22, 2019 at 03:23:51PM +0000, Tristan Bastian wrote:
Hello,
since mainline kernel 4.19 LPAE is no longer working for me and some others
on tegra124-nyan-big.
Is this a known problem with a fix already available?
The defconfig to compile the kernel can be found here:
github.com/reey/PKGBUILDs/blob/master/core/linux-nyan/nyan-big_defconfig
Basically we are only getting 2 GB instead of 4 GB of memory.
Kernel 4.18 still gives us 4 GB.
Both kernels are configured with CONFIG_ARM_LPAE=y.
All newer kernel versions also have this bug..
Looking at the git log, I can only find one possibly suspicious change:
commit 482997699ef038af7553399d49b7ba74c3301424
Author: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
Date: Mon Jul 9 18:05:17 2018 +0200
ARM: tegra: Fix unit_address_vs_reg DTC warnings for /memory
Add a generic /memory node in each Tegra DTSI (with empty reg property,
to be overidden by each DTS) and set proper unit address for /memory
nodes to fix the DTC warnings:
arch/arm/boot/dts/tegra20-harmony.dtb: Warning (unit_address_vs_reg):
/memory: node has a reg or ranges property, but no unit name
The DTB after the change is the same as before except adding
unit-address to /memory node.
Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
Reviewed-by: Stefan Agner <stefan@xxxxxxxx>
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
I suppose this could result in the bootloader failing to find the memory
node when trying to patch up the memory banks. It looks like U-Boot
handles this properly by ignoring the unit-address when looking up nodes
by name (without unit-address), but I suspect that coreboot may not be
doing this. I'm assuming that coreboot is what you're using as
bootloader?
If coreboot behaves similarly to U-Boot, it'll create a new node if it
can't find a matching one, so you may be able to inspect the device tree
that was passed to the kernel (/sys/firmware/fdt should have the binary
and /sys/firmware/devicetree should have a directory tree representation
of the device tree).
Thierry
Hi Thierry,
I'm using coreboot.
But what I can also tell is, that when you use U-Boot chainloaded to coreboot, LPAE is also not working with older kernel revisions like 4.18.
I only found a single memory entry in /sys/firmware/devicetree/ "memory@80000000"...
BTW: @Thierry, I'm reverting this patch: https://patchwork.kernel.org/patch/9516105/ because otherwise I'm getting a blank screen on bootup. Is there any fix for that going upstream?
Thanks,
Tristan
Hi Thierry,
I have to correct myself.
I found two memory entries in /sys/firmware/devicetree/base/.
One called "memory@80000000" and the other one just "memory".
Thanks,
Tristan
