Stephen, OK, thanks for testing! I will rev the patch and resend in a little bit. -Doug --- On Fri, Sep 30, 2011 at 3:11 PM, Stephen Warren <swarren@xxxxxxxxxx> wrote: > Doug Anderson wrote at Monday, September 26, 2011 12:24 PM: >> With this change we automatically detect which UART to use for >> earlyprintk (and for printing during decompression). The >> detection involves coordination with the bootloader: it's expected >> that the bootloader will leave a 'D' (for [D]ebug) in the UART >> scratchpad register for whichever UART we should use for debugging. > > This works fine on Tegra20; there, even if the UART clock is off and/or > the UART is in reset, you can still read the UART_SCR register (and get > a bogus value) without the system hanging. > > However, I just tested on Tegra30, and the behavior has changed; if either > a UART is in reset /or/ the UART clock is stopped, then the system hangs > when UART_SCR is read. > > As such, this change will cause Tegra30 to fail to boot. I'd rather it > was augmented to check the clock enable and module reset bits as well > as the scratch register value in all cases. > > Yes, I know mainline doesn't support Tegra30 yet, but we're very close > to posting the first few patches to start enabling it, and I wouldn't > want to break it right before that! > > -- > nvpublic > > -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
