Changes between Version 6 and Version 7 of troubleshooting

Timestamp:

09/22/2026 04:41:34 PM (5 hours ago)

Author:

Tim Harvey

Comment:

updated early serial debug

troubleshooting

@@ -93 +93 @@
 Typically the serial drivers don't get initialized until after some of the more critical components. This can result in any kernel crash/hang not reporting anything from the serial console after {{{'Starting kernel ....'}}}
 
-For platforms that early serial support you can enable this in the kernel config. For example on a Ventana board (all ventana boards use ttymxc1 (UART2) for serial console):
- * make menuconfig
-  - Kernel hacking -> Kernel low-level debugging functions -> Kernel low-level debugging port (i.MX6Q/DL Debug UART)
-  - Kernel hacking -> Kernel low-level debugging functions -> i.MX Debug UART Port Selection : 2
- * results in the following additions to .config:
-{{{
-CONFIG_DEBUG_LL=y
-CONFIG_DEBUG_IMX6Q_UART=y
-CONFIG_DEBUG_IMX_UART_PORT=2
-CONFIG_DEBUG_LL_INCLUDE="debug/imx.S"
-CONFIG_DEBUG_UNCOMPRESS=y
-CONFIG_EARLY_PRINTK=y
-CONFIG_EARLY_PRINTK_DIRECT=y
+For platforms that early serial support you can enable this in the kernel config.
+
+For modern kernels this requires 'CONFIG_SERIAL_EARLYCON=y' to be enabled in the kernel config in addition to specifying the serial port details via the kernel cmdline:
+ * i.MX95 Catalina ttyLP0 (lpuart1):
+{{{#!bash
+earlycon=lpuart32,mmio32,0x44380010,115200
 }}}
- * Finally, some kernels require a special parameter to be passed in through the bootloader.  See below for instructions:
-{{{#!bash
-setenv extra ${extra} earlyprintk=serial,${console},${baudrate}
-saveenv
-}}}
-
-For newport, Early console is compiled into the kernel and to enable it make sure you boot with:
-{{{#!bash
-console=ttyAMA0,115200n8 earlycon=pl011,0x87e028000000 cma=64M
-}}}
-
-For venice, Early console is compiled into the kernel and to enable it make sure you boot with:
+ * i.MX8M Venice ttymxc1 (uart2):
 {{{#!bash
 console=ttymxc1,115200 earlycon=ec_imx6q,0x30890000,115200
 }}}
+ * CN80xx Newport ttyAMA0:
+{{{#!bash
+console=ttyAMA0,115200n8 earlycon=pl011,0x87e028000000
+}}}
+
 
 [=#sysrq]