diff options
Diffstat (limited to 'dev/uart.cc')
| -rw-r--r-- | dev/uart.cc | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/dev/uart.cc b/dev/uart.cc index 3c4ab6d04..caa169a2e 100644 --- a/dev/uart.cc +++ b/dev/uart.cc @@ -73,17 +73,28 @@ Uart::IntrEvent::process() } +/* The linux serial driver (8250.c about line 1182) loops reading from + * the device until the device reports it has no more data to + * read. After a maximum of 255 iterations the code prints "serial8250 + * too much work for irq X," and breaks out of the loop. Since the + * simulated system is so much slower than the actual system, if a + * user is typing on the keyboard it is very easy for them to provide + * input at a fast enough rate to not allow the loop to exit and thus + * the error to be printed. This magic number provides a delay between + * the time the UART receives a character to send to the simulated + * system and the time it actually notifies the system it has a + * character to send to alleviate this problem. --Ali + */ void Uart::IntrEvent::scheduleIntr() { + static const Tick interval = (Tick)((Clock::Float::s / 2e9) * 450); DPRINTF(Uart, "Scheduling IER interrupt for %#x, at cycle %lld\n", intrBit, - curTick + (ticksPerSecond/2000) * 350); + curTick + interval); if (!scheduled()) - /* @todo Make this cleaner, will be much easier with - * nanosecond time everywhere. Hint hint Nate. */ - schedule(curTick + (ticksPerSecond/2000000000) * 450); + schedule(curTick + interval); else - reschedule(curTick + (ticksPerSecond/2000000000) * 450); + reschedule(curTick + interval); } Uart::Uart(const string &name, SimConsole *c, MemoryController *mmu, Addr a, |