Messages in this thread | | | Date | Sun, 25 May 2008 00:22:20 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH 1/1] UIO: Add a write() function to enable/disable interrupts |
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On Fri, 23 May 2008, Greg KH wrote:
> On Fri, May 23, 2008 at 01:55:57PM +0200, Hans J. Koch wrote: > > Sometimes it is necessary to enable/disable the interrupt of a UIO device > > from the userspace part of the driver. With this patch, the UIO kernel driver > > can implement an "irqcontrol()" function that does this. Userspace can write > > an s32 value to /dev/uioX (usually 0 or 1 to turn the irq off or on). The > > UIO core will then call the driver's irqcontrol function. > > Why not just a new sysfs file for the uio device, irq_enabled, or > something like that? That way our main read/write path is left alone.
It makes a certain amount of sense to use write. You hold the device file descriptor anyway for the read (wait for interrupt) operation, so using the same file descriptor is not a too bad idea:
while (!stop) {
/* wait for interrupt */ read(fd);
do_stuff();
/*reenable interrupt */ write(fd); }
I thought about using a sysfs entry for a while, but looking at the actual use case made the write() solution a more natural choice.
Thanks,
tglx
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