Micropython easily gets panic after registering LVGL log print callback function #398
Description
LVGL doesn't provide feature to change log level during runtime, so I had to use lv.log_register_print_cb() to set a python function as the print callback to control log level. But I encountered memory problem, which always cause MPY system panic.
Microython 1.26.1
LVGL 9.3 (latest lv_binding_micropython commit f33add0)
On ESP32-C3, IDF 5.4.2
A fatal error occurred. The crash dump printed below ....
....
Guru Meditation Error: Core 0 panic'ed (Instruction access fault). Exception was unhandled.
My lv_conf.h
#if LV_USE_LOG
/** Set value to one of the following levels of logging detail:
* - LV_LOG_LEVEL_TRACE Log detailed information.
* - LV_LOG_LEVEL_INFO Log important events.
* - LV_LOG_LEVEL_WARN Log if something unwanted happened but didn't cause a problem.
* - LV_LOG_LEVEL_ERROR Log only critical issues, when system may fail.
* - LV_LOG_LEVEL_USER Log only custom log messages added by the user.
* - LV_LOG_LEVEL_NONE Do not log anything. */
#define LV_LOG_LEVEL LV_LOG_LEVEL_TRACE
/** - 1: Print log with 'printf';
* - 0: User needs to register a callback with `lv_log_register_print_cb()`. */
#define LV_LOG_PRINTF 0
/** Set callback to print logs.
* E.g `my_print`. The prototype should be `void my_print(lv_log_level_t level, const char * buf)`.
* Can be overwritten by `lv_log_register_print_cb`. */
#define LV_LOG_PRINT_CB mp_lv_log_cb
/** - 1: Enable printing timestamp;
* - 0: Disable printing timestamp. */
#define LV_LOG_USE_TIMESTAMP 1
/** - 1: Print file and line number of the log;
* - 0: Do not print file and line number of the log. */
#define LV_LOG_USE_FILE_LINE 1
/* Enable/disable LV_LOG_TRACE in modules that produces a huge number of logs. */
#define LV_LOG_TRACE_MEM 1 /**< Enable/disable trace logs in memory operations. */
#define LV_LOG_TRACE_TIMER 1 /**< Enable/disable trace logs in timer operations. */
#define LV_LOG_TRACE_INDEV 1 /**< Enable/disable trace logs in input device operations. */
#define LV_LOG_TRACE_DISP_REFR 1 /**< Enable/disable trace logs in display re-draw operations. */
#define LV_LOG_TRACE_EVENT 1 /**< Enable/disable trace logs in event dispatch logic. */
#define LV_LOG_TRACE_OBJ_CREATE 1 /**< Enable/disable trace logs in object creation (core `obj` creation plus every widget). */
#define LV_LOG_TRACE_LAYOUT 1 /**< Enable/disable trace logs in flex- and grid-layout operations. */
#define LV_LOG_TRACE_ANIM 1 /**< Enable/disable trace logs in animation logic. */
#define LV_LOG_TRACE_CACHE 1 /**< Enable/disable trace logs in cache operations. */
#endif /*LV_USE_LOG*/My python code:
import lvgl as lv
# {'TRACE': 0, 'INFO': 1, 'WARN': 2, 'ERROR': 3, 'USER': 4, 'NONE': 5}
LV_LOG_LEVEL = lv.LOG_LEVEL.WARN
def lv_log_cb(level, content):
if level >= LV_LOG_LEVEL:
print(content)
# gc.collect() # without this, MPY easily panic. But adding this will make it very slow
lv.log_register_print_cb(lv_log_cb)
disp1 = None
def init_lv():
global disp1
lv.init()
disp1 = lv.display_create(LCD_W, LCD_H)
disp1.set_color_format(lv.COLOR_FORMAT.I1)
disp1.set_buffers(lv_disp_bufarr,
None,
len(lv_disp_bufarr),
lv.DISPLAY_RENDER_MODE.FULL,
)
disp1.set_flush_cb(flush_cb)
init_lv()
scr = lv.obj()
lv.screen_load(scr)
lv.refr_now(disp1)
# add some widgets
lv.refr_now(disp1)
# add some widgets . Easily MPY system panic !!!