Hi, * Romain Naour <romain.naour@xxxxxxxx> [220204 13:39]: > It seems that the driver fail to read the UART_LCR register from > omap8250_set_mctrl(): > > "lcr = serial_in(up, UART_LCR);" > > PC is at mem_serial_in+0x2c/0x30 > LR is at omap8250_set_mctrl+0x48/0xb0 > > The problem only occurs with a -rt kernel, I tried with several kernel version: > 5.10-rt, 5.15-rt and 5.17-rt. > > I'm not able to reproduce the issue with a standard kernel. Interesting, what's the exception you get with the -rt kernel? Is it an unhandled external abort or something else? > While looking at the git history, I noticed this commit [3] about "flakey idling > of uarts and stop using swsup_sidle_act". > > So I removed the SYSC_QUIRK for uart IP revision 0x50411e03 and it fixed my issue. Hmm. > Is the SYSC_QUIRK for omap4 still needed ? Is it safe to remove it ? > It seems this issue was introduced while dropping the legacy platform data > (between 4.19 and 5.4 kernels). AFAIK it's still needed, but maybe we can disable it for am57xx though. Regards, Tony
