On Mon, Mar 9, 2015 at 8:05 AM, Alan Cox <alan@xxxxxxxxxxxxxxx> wrote: > Ah no - I meant what is their official software workaround for existing > parts with the bug ? Presumably they have an errata document that > discusses this and the correct methods they recommend to avoid the > hang ? As far as I know, the only advice they provided was rather naive. The documentation I saw suggested stashing a copy of the LCR and then rewriting it when the special LCR write failed interrupt was raised. That approach was not workable as the LCR might be written while the interrupt is masked causing the sequence of register writes to occur in an order other than what was desired. Additionally, when the LCR needed to be re-written but the UART stayed busy, the interrupt would keep firing and the driver would starve out everything else on the CPU. The current workaround of clearing fifos and retrying a fixed number of times isn't ideal but I'm not sure what else can be done given the way this hardware works. Additional background is in c49436b657d0a56a6ad90d14a7c3041add7cf64d -Tim -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
