On 2/11/20 12:55 AM, Christophe Leroy wrote:
Le 10/02/2020 à 13:55, Larry Finger a écrit :
On 2/9/20 12:19 PM, Christophe Leroy wrote:
Do you have CONFIG_TRACE_IRQFLAGS in your config ?
If so, can you try the patch below ?
https://patchwork.ozlabs.org/patch/1235081/
Otherwise, can you send me your .config and tell me exactly where it stops
during the boot.
Christophe,
That patch did not work. My .config is attached.
It does boot if CONFIG_VMAP_STACK is not set.
The console display ends with the "DMA ranges" output. A screen shot is also
appended.
Larry
Hi,
I tried your config under QEMU, it works.
In fact your console display is looping on itself, it ends at "printk:
bootconsole [udbg0] disabled".
Looks like you get stuck at the time of switching to graphic mode. Need to
understand why.
I'm not surprised that a real G4 differs from QEMU. For one thing, the real
hardware uses i2c to connect to the graphics hardware.
I realized that the screen was not scrolling and output was missing. To see what
was missed, I added a call to btext_clearscreen(). As you noted, it ends at the
bootconsole disabled statement.
As I could not find any console output after that point, I then turned off the
bootconsole disable. I realize this action may cause a different problem, but in
this configuration, the computer hit a BUG Unable to handle kernel data access
at 0x007a84fc. The faulting instruction address was 0x00013674. Those addresses
look like physical, not virtual, addresses.
I then added pr_info statements to bracket the failure. In file
drivers/video/fbdev/core/fb_ddc.c, the code reaches line 66, which is
algo_data->setsda(algo_data->data, 1);
Both pointers seem OK with algo_data = 0xeedfb4bc, and algo_data->data =
0xeedb25c. The code faults before returning. I then annotated that callback
routine radeon_gpio_setsda(), and found that execution is OK to the end of the
routine, but the fault happens on the return from this routine as though the
stack were corrupted.
I will be busy for about 8 hours, but if you can think of any debugging I can do
on this routine, please let me know.
Thanks,
Larry
