On 04/07/2024 07:03, Greg KH wrote:
On Wed, Jul 03, 2024 at 05:33:57PM +0200, Jocelyn Falempe wrote:
This series adds a new panic screen, with the kmsg data embedded in a QR-code.
The main advantage of QR-code, is that you can copy/paste the debug data to a bug report.
The QR-code encoder is written in rust, and is very specific to drm_panic.
The reason is that it is called in a panic handler, and thus can't allocate memory, or use locking.
The rust code uses a few rust core API, and provides only two C entry points.
There is no particular reason to do it in rust, I just wanted to learn rust, and see if it can work in the kernel.
If you want to see what it looks like, I've put a few screenshots here:
https://github.com/kdj0c/panic_report/issues/1
Cool, this idea has been floating around for decades, here's the last
attempt at this back in 2014:
https://lore.kernel.org/all/1395093587-2583-1-git-send-email-teobaluta@xxxxxxxxx/
Yes, I've looked at this, but drawing a QR-code in the middle of fbcon
was a bit complex. Now with drm panic, there is a proper infrastructure
to display the QR code, and make sure it won't be overwritten.
--
Jocelyn
Jocelyn Falempe (4):
drm/panic: Add integer scaling to blit()
drm/rect: add drm_rect_overlap()
drm/panic: simplify logo handling
drm/panic: Add a qr_code panic screen
drivers/gpu/drm/Kconfig | 29 +
drivers/gpu/drm/Makefile | 1 +
drivers/gpu/drm/drm_drv.c | 3 +
drivers/gpu/drm/drm_panic.c | 338 +++++++++--
drivers/gpu/drm/drm_panic_qr.rs | 989 ++++++++++++++++++++++++++++++++
Wait, we can put .rs files in any directory now? I didn't think that
worked properly yet.
Yes, thanks to the work of the rust-for-linux team. When I started to
work on this, I needed a few workarounds to make my rust code compile.
But since 6.10-rc1, I was able to drop them all. Also for this simple
case, I don't use bindgen, because there are only 2 Rust functions, that
I need to call from C.
thanks,
greg k-h
--
Jocelyn
