On Wednesday 07 March 2012 03:23:42 Amit Virdi wrote:
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?
if it works on your platform, and you compile it test it for others, and we agree it looks correct, and no one else wants to runtime test it to verify, i think it's fine to merge. if there's a problem, someone will notice and let us know ;). -mike