Re: Using serial driver 16550A in poll mode without interruptconnected

From: Alan Cox
Date: Wed Oct 12 2011 - 09:53:20 EST


> Driver is probed with no IRQ (NO_IRQ = -1 on Microblaze)
> 83e00000.serial: ttyS0 at MMIO 0x83e01003 (irq = -1) is a 16550A

Zero means no IRQ. NO_IRQ is a legacy internal thing for the old IDE code
so not something other code should be using. Setting the IRQ to -1 is
bogus and will confuse the rest of the kernel.

> Is it possible to use serial driver without IRQ - or blocking IRQ, etc.?

Within limits - it kills your power management and data rates because of
the continual polling.

Alan
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