[U-Boot] [PATCH v2 2/5] ehci-hcd: Boost transfer speed

Benoît Thébaudeau
2012-07-20T13:17:38Z

On Friday 20 July 2012 13:37:37 Stefan Herbrechtsmeier wrote:
> Am 20.07.2012 13:26, schrieb Beno?t Th?baudeau:
> > + int xfr_bytes = min(left_length,
> > + (QT_BUFFER_CNT * 4096 -
> > + ((uint32_t)buf_ptr & 4095)) &
> > + ~4095);
> Why you align the length to 4096?

It's to guarantee that each transfer length is a multiple of the max packet
length. Otherwise, early short packets are issued, which breaks the transfer and
results in time-out error messages.

Regards,
Beno?t