how to manage or resolve log of SPI interrupt in embedded linux-CodePudding

My SOC with embedded linux OS communicate with another chip by SPI protocol, when I monitor the /var/log/kern.log file I see these messages that is written in this file with a high speed and rate(And this event causes a sharp decrease in the free memory of the system) :

2022-11-09T15:28:38.827661 00:00 mcu-v1 kernel: [  513.748802] fsl_spi e0007000.spi: 
fsl_spi_irq: events 300
2022-11-09T15:28:38.827758 00:00 mcu-v1 kernel: [  513.748855] fsl_spi e0007000.spi: 
fsl_spi_irq: events 300
2022-11-09T15:28:38.838743 00:00 mcu-v1 kernel: [  513.759301] fsl_spi e0007000.spi: 
fsl_spi_irq: events 300
2022-11-09T15:28:38.838843 00:00 mcu-v1 kernel: [  513.759347] fsl_spi e0007000.spi: 
fsl_spi_irq: events 300
2022-11-09T15:28:38.838885 00:00 mcu-v1 kernel: [  513.759418] fsl_spi e0007000.spi: 
fsl_spi_irq: events 300
2022-11-09T15:28:38.838921 00:00 mcu-v1 kernel: [  513.759457] fsl_spi e0007000.spi: 
fsl_spi_irq: events 300
2022-11-09T15:28:38.850540 00:00 mcu-v1 kernel: [  513.769821] fsl_spi e0007000.spi: 
fsl_spi_irq: events 300
2022-11-09T15:28:38.850703 00:00 mcu-v1 kernel: [  513.769862] fsl_spi e0007000.spi: 
fsl_spi_irq: events 300
2022-11-09T15:28:38.850753 00:00 mcu-v1 kernel: [  513.769960] fsl_spi e0007000.spi: 
fsl_spi_irq: events 300
2022-11-09T15:28:38.850788 00:00 mcu-v1 kernel: [  513.770003] fsl_spi e0007000.spi: 
fsl_spi_irq: events 300

I set the log_level in kernel command line with 2 to ignore this messages(To prevent memory consumption )! But the message is still being written ! I read the kernel source(v 4.14) But I did not understand!

What does this message indicate? And how to solve this problem ?

CodePudding user response：

What does this message indicate?

The message seems to be for debugging, a notice that this ISR handled an event.
In drivers/spi/spi-fsl-spi.c:

static irqreturn_t fsl_spi_irq(s32 irq, void *context_data)
{
    ...

    /* Get interrupt events(tx/rx) */
    events = mpc8xxx_spi_read_reg(&reg_base->event);
    if (events)
        ret = IRQ_HANDLED;

    dev_dbg(mspi->dev, "%s: events %x\n", __func__, events);    <== msg generator
    ...
    return ret;
}

a debug console message is generated unconditionally every time the ISR is executed.

And how to solve this problem ?

The messages do not indicate any "problem" that needs resolution. Every SPI interrupt handled will generate the message. Yes, it's a bit noisy.

For the problem of excessive messages, check your kernel configuration.
Is CONFIG_SPI_DEBUG enabled? If so, then disable it, and rebuild the kernel.