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From: Amit Virdi <amit.virdi@st.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] USB:host: Attribute packed removed from usb structures
Date: Wed, 7 Mar 2012 13:53:42 +0530	[thread overview]
Message-ID: <4F571B0E.7080604@st.com> (raw)
In-Reply-To: <201203061111.14475.vapier@gentoo.org>

Mike,

>>
>> I did the changes suggested by you and tested the build. The issue
>> didn't come up. Then I reverted the code to the original (attributes
>> retained and ehci directly de-referencing the pointers. The issue didn't
>> come here too.
>>
>> Today, I used armv7-linux-gcc (GCC) v4.6.2
>> So I suspect there has been some fix done in the GCC.
>>
>> Now, even with the packed attributes, the word fields are accessed
>> word-by-word in contrast to the earlier observed behavior
>> (byte-by-byte). I could see ldr and str in the disassembly.
>>
>> May be, we can discard this patch and keep drivers/usb/host/ehci.h intact.
>
> not sure ... in general, device registers should be accessed with io.h helpers
> instead of dereferenced by volatile pointers.  i can think of cases on Blackfin
> where the io.h helpers would be required, and even using volatile pointers
> could result in misbehavior.

If you guys agree, I can float the patch but how can we distribute the 
responsibility for testing on other architectures?

Thanks
Amit Virdi

  reply	other threads:[~2012-03-07  8:23 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-24 11:58 [U-Boot] [PATCH] USB:host: Attribute packed removed from usb structures Amit Virdi
2012-02-24 19:18 ` Mike Frysinger
2012-02-27 10:02   ` Amit Virdi
2012-02-27 18:25     ` Mike Frysinger
2012-02-25 10:12 ` Albert ARIBAUD
2012-02-27  7:16   ` Vipin Kumar
2012-02-27 13:14     ` Marek Vasut
2012-02-27 18:26       ` Mike Frysinger
2012-02-27 20:53         ` Marek Vasut
2012-02-28  0:56           ` Mike Frysinger
2012-02-29 10:25             ` Amit Virdi
2012-03-06 12:06               ` Amit Virdi
2012-03-06 12:51                 ` Marek Vasut
2012-03-07  8:30                   ` Amit Virdi
2012-03-07 11:38                     ` Marek Vasut
2012-03-07 12:12                       ` Amit Virdi
2012-03-06 16:11                 ` Mike Frysinger
2012-03-07  8:23                   ` Amit Virdi [this message]
2012-03-07 13:33                     ` Mike Frysinger
2012-03-07 13:49                       ` Amit Virdi

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