Hello Mike,

On 2/28/2012 6:26 AM, Mike Frysinger wrote:
On Monday 27 February 2012 15:53:29 Marek Vasut wrote:
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 écrit :
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.

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

i'm not entirely sure what you're asking, but i think you're pointing to the
right answer: drivers/usb/host/ehci.h:ehci_{read,write}l() should *not* be
casting/derferencing the pointers directly.  they should instead be using
standard {read,write}l() funcs from asm/io.h.

Amit: can you post a new patch that does that instead ?  don't touch the
packed attribute, but change ehci_readl() to use readl() and ehci_writel() to
use writel() ?

I'll make the changes and post the patch after testing successfully.

Thanks
Amit Virdi
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