lkml.org 
[lkml]   [2011]   [Jun]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] USB: ehci: use packed, aligned(4) instead of removing the packed attribute
On Mon, 20 Jun 2011, Russell King - ARM Linux wrote:

> On Mon, Jun 20, 2011 at 06:58:45PM +0200, Arnd Bergmann wrote:
> > We are also going to change the ARM implementation to always do 32 bit
> > accesses in readl/writel, but the patch that went into the ehci driver
> > was correct nonetheless.
>
> Not without someone doing a comparitively large amount of work to analyze
> the effect of any change there and make sure that it doesn't have a
> negative impact to drivers.

This thread prompted me to investigate a bit. I have vague memories for
the reasons why we decided to use plain C for the IO accessors as the
inline assembly version didn't produce nearly the same code quality. It
seems that GCC improved quite a bit there, and from a quick
investigation, it looks like comparable code is being generated with the
C and the inline asm versions with a recent enough GCC. This is
certainly the case with the version causing issues with packed
structures.


Nicolas


\
 
 \ /
  Last update: 2011-06-20 21:31    [W:0.146 / U:0.156 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site