mdelay causes kernel panic

mathew_k_t — Tue, 16 Jun 2020 05:22:19 GMT

Hi,

I'm using an i.mx6ull based custom board and is battery powered. I have an LCD device driver using i2c. I need to enable all segments during booting and wait for three seconds then disable all segments. Once all segments are turned off, I need to print some messages on the display.

For waiting three seconds I have used mdelay(3000). This causes kernel panic when it is powered from a battery(Battery was fully charged and there is no severe voltage drop). It works as expected when it is powered from USB. Also, if we split the mdelay(3000) to (mdelay(1000) X 3 times) or (mdelay(2000) and mdelay(1000)), no issue is found. What would be the reason for it? Any workaround for this?
Since mdelay was causing panic, I created a timer delay and initialized a tasklet for displaying a message from timer ISR. There are around 30-40 i2c transactions for displaying the message. While executing this it throws.

It takes a long time to boot. Is it a clock stretching? What will be the best solution for the given requirement?

This is bit critical. Please reply fast.

Thanks in advance.

Re: mdelay causes kernel panic

igorpadykov — Tue, 16 Jun 2020 09:21:14 GMT

Hi mathew_k_t

seems mdelay is blocking other tasks which could cause linux problems:

https://www.kernel.org/doc/Documentation/timers/timers-howto.txt

msleep() vs. mdelay() – Energiequant

Best regards
igor
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i.MX ProcessorsのトピックRe: mdelay causes kernel panic

mdelay causes kernel panic

Re: mdelay causes kernel panic