From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marek Vasut <marek.vasut@gmail.com>
Date: Mon, 27 Feb 2012 21:53:29 +0100
Subject: [U-Boot] [PATCH] USB:host: Attribute packed removed from usb
	structures
In-Reply-To: <201202271327.01060.vapier@gentoo.org>
References: <1330084720-16878-1-git-send-email-amit.virdi@st.com>
	<201202271414.26549.marek.vasut@gmail.com>
	<201202271327.01060.vapier@gentoo.org>
Message-ID: <201202272153.29932.marek.vasut@gmail.com>
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To: u-boot@lists.denx.de

> On Monday 27 February 2012 08:14:26 Marek Vasut wrote:
> > > On 2/25/2012 3:42 PM, Albert ARIBAUD wrote:
> > > > Le 24/02/2012 12:58, Amit Virdi a ?crit :
> > > >> Packed attribute is forcing a bytewise write on device registers,
> > > >> there by, resulting in a misbehavior on gcc-4.4.1.
> > > >> Reverting the structures to non-packed
> > > > 
> > > > If (just asking, not asserting) the issue is caused by fields being
> > > > u8 where u8 access is not possible, then should you not make the
> > > > fields u16 / u32 according to access requirements?
> > > 
> > > The problem is not with the fields being of a different width. AFAIK,
> > > the packed attribute changes the generated code to access even the word
> > > field elements in a byte by byte manner
> > > 
> > > Infact, there is a discussion on lkml that I can point
> > > https://lkml.org/lkml/2011/4/27/278
> > > 
> > > It seems that the discussion did not lead to a conclusion but it was
> > > sensible (at least for ARM) to remove the packed attribute from this
> > > structure
> > 
> > What does the USB spec say ? It might be a HW bug?
> 
> it isn't covered by the USB spec.  these are structs for hardware registers
> in the EHCI usb host controller.
> -mike

I see ... so replacing them with unions of accessors where it colides might work 
?