Hi, On Wed, Oct 7, 2015 at 5:48 PM, Douglas Anderson <dianders@xxxxxxxxxxxx> wrote: > In (usb: dwc2: reset dwc2 core before dwc2_get_hwparams()) we added an > extra reset to the probe path for the dwc2 USB controllers. This > allowed proper detection of parameters even if the firmware had already > used the USB part. > > Unfortunately, this extra reset is quite slow and is affecting boot > speed. We can avoid the double-reset by skipping the extra reset that > would happen just after the one we added. Logic that explains why this > is safe: > > * As of the CL mentioned above, we now always call dwc2_core_reset() in > dwc2_driver_probe() before dwc2_hcd_init(). > > * The only caller of dwc2_hcd_init() is dwc2_driver_probe(), so we're > guaranteed that dwc2_core_reset() was called before dwc2_hdc_init(). > > * dwc2_hdc_init() is the only caller that passes an irq other than -1 to > dwc2_core_init(). Thus if dwc2_core_init() is called with an irq > other than -1 we're guaranteed that dwc2_core_reset was called before > dwc2_core_init(). > > ...this allows us to remove the dwc2_core_reset() in dwc2_core_init() if > irq is not < 0. > > Note that since "irq" wasn't used in the function dwc2_core_init() > anyway and since select_phy was always set at exactly the same times we > could avoid the reset, we remove "irq" and rename "select_phy" to > "initial_setup" and adjust the callers accordingly. > > Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx> > --- > drivers/usb/dwc2/core.c | 29 ++++++++++++++++++----------- > drivers/usb/dwc2/core.h | 2 +- > drivers/usb/dwc2/hcd.c | 6 +++--- > 3 files changed, 22 insertions(+), 15 deletions(-) Obviously I stupidly forgot to remove the "CHROMIUM" prefix on this patch. :( Sorry about that. I can repost if necessary... -Doug -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
