Re: [RFC PATCH] usb: dwc2: host: Rewrite the microframe scheduler

From: Doug Anderson
Date: Mon Nov 09 2015 - 14:24:18 EST


Hi,

On Fri, Nov 6, 2015 at 5:50 PM, Douglas Anderson <dianders@xxxxxxxxxxxx> wrote:
> The old microframe scheduler was terribly hard to follow and (it seemed
> to me) that it had some bugs in it.
>
> Let's re-write it in a simpler, easier-to-read way. Hopefully this will
> work better.
>
> Note: no known problems are fixed by this patch, and in fact I can see
> very little impact of the microframe scheduler overall.
>
> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
> ---
> drivers/usb/dwc2/hcd_queue.c | 72 ++++++++++++++++++++------------------------
> 1 file changed, 32 insertions(+), 40 deletions(-)

Self-NAKing this change.

I wrote up some test code to help visualize how things were scheduled.
That proved that the old function is pretty broken, but the new
function not only has a typo (using "i" instead of "j" in a few
places) but also suffers from some of the same problems as the old
function.

It might be easy to use the bitmap functions to implement this easily
/ properly. I'll see if I can do that.

-Doug
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