Date: Fri, 6 Jan 2006 18:38:46 +0000
From: Russell King <rmk+lkml@arm.linux.org.uk>
To: Oliver Neukum <oliver@neukum.org>
Cc: linux-usb-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org
Subject: Re: need for packed attribute
Message-ID: <20060106183846.GF16093@flint.arm.linux.org.uk>
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	linux-usb-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org
References: <200601061915.43961.oliver@neukum.org>
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On Fri, Jan 06, 2006 at 07:15:43PM +0100, Oliver Neukum wrote:
> Hi,
> 
> is there any architecture for which packed is required in structures like this:
> 
> /* All standard descriptors have these 2 fields at the beginning */
> struct usb_descriptor_header {
> 	__u8  bLength;
> 	__u8  bDescriptorType;
> };

sizeof(struct usb_descriptor_header) will be 4 on ARM.  If this
concerns you, you need to pack the structure thusly:

struct usb_descriptor_header {
	__u8  bLength;
	__u8  bDescriptorType;
} __attribute__((packed));
	

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core
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