Messages in this thread | | | Date | Fri, 21 Sep 2007 15:36:05 +0100 (BST) | From | "Maciej W. Rozycki" <> | Subject | Re: [PATCH] kernel/printk.c: Concerns about the console handover |
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On Fri, 21 Sep 2007, Russell King wrote:
> I suspect the correct fix for this is to take the fix in the ARM tree > for serial_core's console initialisation, and ensure that zs.c handles > the power management of the port (enabling/disabling transmitter) > in the power management callback.
Hmm, it sounds a bit hackish to me. The serial part is from the 1970s -- nobody thought of power management back then. And even though the DECstation is about 20 years younger, it does not provide any means for power management either -- it is a workstation/server class system after all.
> You can find the fix in the mbox archive: > > http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cut/arm:devel.mbox
Hmm, nothing of relevance there.
I see no problem with implementing the ->pm() call as something like:
void zs_pm(struct uart_port uport, unsigned int state, unsigned int oldstate) { struct zs_port *zport = to_zport(uport);
if (state < 3) zport->regs[5] |= TxENAB; else zport->regs[5] &= ~TxENAB; write_zsreg(zport, R5, zport->regs[5]); }
itself, but it looks more like a workaround than a fix to me. I'll have to think about it and also double-check it is safe. The SCC is about as complicated as you can get with a serial port.
Thanks for the hint though.
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