On 10/6/23 10:18, Philippe Mathieu-Daudé wrote:
On 6/10/23 10:13, Cédric Le Goater wrote:
On 10/6/23 08:47, Philippe Mathieu-Daudé wrote:
QEMU consumes some device tree blobs, so these have been committed
to the tree in as firmware, along with the device tree source used
to generate them. We know the blobs are "good enough" to have QEMU
boot a system, so we don't really maintain and rebuild the sources.
These blobs were generated with older 'dtc' binaries. We use the
v1.6.1 version since 2021 (commit 962fde57b7 "dtc: Update to version
1.6.1").
Since commit 6e0dc9d2a8 ("meson: compile bundled device trees"),
if dtc binary is available, it is directly used to compile the
device tree sources. New versions of 'dtc' add checks which display
warnings or errors. Our sources are a bit old, so dtc v1.6.1 now
emit the following warnings on a fresh build:
[163/3414] Generating pc-bios/canyonlands.dts with a custom command
pc-bios/canyonlands.dts:47.9-50.4: Warning (unit_address_vs_reg):
/memory: node has a reg or ranges property, but no unit name
...
From QEMU perspective, these warnings are not really useful. It is
the responsibility of developers adding DT source/blob to QEMU
repository to check the source doesn't produce warnings, but as
long as the blob is useful enough, QEMU can consume it. So these
warnings don't add any value, instead they are noisy and might
distract us to focus on important warnings. Better disable them.
'dtc' provides the '--quiet' option for that:
$ dtc --help
Usage: dtc [options] <input file>
Options: -[qI:O:o:V:d:R:S:p:a:fb:i:H:sW:E:@AThv]
-q, --quiet
Quiet: -q suppress warnings, -qq errors, -qqq all
Update meson to disable these unuseful DTC warnings.
Why not try fixing the .dts instead ? These still exist under Linux :
./arch/powerpc/boot/dts/canyonlands.dts
./arch/powerpc/boot/dts/bamboo.dts
Because QEMU != Linux, and there isn't always overlap between
communities?
sure but bamboo.dts came from Linux. So this should be safe to update.
Alex Graf did 10 years ago.
I can not tell for the sam460ex. It is probably safer to keep it as it is.
Sweeping dtc warnings under the rug for all .dts doesn't seem a good idea.
Should we get rid of the .dts and only keep the .dtb then ?