Upgrading my Chumby 8 kernel part 12: UART woes
Doug Brown faced challenges with UART driver while upgrading Chumby 8 kernel. He traced delays to a Broadcom BCM63xx UART driver commit, resolving output delay by manually triggering data transmission, revealing driver complexities.
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In a series of blog posts, Doug Brown details his challenges with the UART driver while upgrading the kernel on his Chumby 8 device. Initially opting for the deprecated pxa driver due to issues with the 8250_pxa driver, he later encountered delays in console output after updating to Linux 6.9. Through a Git bisect process, he traced the problem to a commit intended to fix issues with the Broadcom BCM63xx UART driver. Despite the logical changes made in the commit, Doug found that the UART output was delayed until a character was manually input. By analyzing register values and toggling interrupts, he managed to manually trigger the transmission of pending data. Doug's debugging efforts revealed insights into the UART's behavior and highlighted the complexities of driver interactions in kernel development.
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