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input_event for 64-bit kernel and 32-bit userland.

To: linux-mips@linux-mips.org
Subject: input_event for 64-bit kernel and 32-bit userland.
From: Pavel Kiryukhin <savl@dev.rtsoft.ru>
Date: Wed, 02 Jun 2004 14:06:10 +0400
Cc: Pavel Kiryukhin <savl@dev.rtsoft.ru>
Original-recipient: rfc822;linux-mips@linux-mips.org
Sender: linux-mips-bounce@linux-mips.org
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Hi all,
I stuck in simple situation:
USB mouse (or keyboard). n64 kernel (2.4.20), n32 userland.

Userspace application tries to read "input_event" (16 bytes) from "/dev/input/event0" [ read(fd,&key_ev, sizeof(key_ev)) ], input core driver treats "input_event" as 24 bytes structure. It is due to different size of "timeval" (and finally "long") in n64 kernel and n32 userland.

Application gets some garbage as mouse events . No solutions like "ioctl wrappers" applicable in this case.

I don't want to change any arch independent files, but can not find any
acceptable solution. It looks like headers "/usr/include/linux/input.h" in root file system and "/include/linux/input.h" in kernel should be the same, (All works fine as soon as I declare a new "input_event" structure in user application that corresponds in size to kernel
structure - but this is not acceptable).

Can anybody advice me what to do with the difference in "input_event"
structure sizes in o32/n32 userland and n64 kernel? Just a general approach that can be used when driver's read/write operation treat some values as 64 bit while user application tries to read/write 32-bit values (based on the same headers).

Please, don't kick me if solution is simple and obvious.
---
Thanks,
Pavel Kiryukhin.




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