On Fri, Oct 31, 2014 at 02:06:14AM +0000, yoshihiro shimoda wrote: > Hi Simon-san, > > > On Wed, Oct 29, 2014 at 08:19:30PM +0900, Yoshihiro Shimoda wrote: > > > Hi Magnus-san, > > > > > > (2014/10/29 15:53), Magnus Damm wrote: > < snip > > > > > > > > > Hi Shimoda-san, > > > > > > > > Thanks for your patch. I'm fine with this patch as a first step, but > > > > I'm wondering what the reason is to prioritize USB 2.0 over USB 3.0? > > > > > > I investigated this reason today, and I found the reason is > > > request_firmware(). I checked the following environments: > > > > > > Case 1: xHCI and EHCI and OHCI are enabled "=y" > > > Case 2: xHCI and EHCI and OHCI are loadable modules "=m" > > > Case 3: xHCI and EHCI and OHCI are enabled "=y", > > > and CONFIG_EXTRA_FIRMWARE is enabled > > > > > > The results are: > > > - In "Case 1", EHCI and OHCI are probed first because xHCI didn't find the firmware. > > > - In "Case 2" and "Case 3", xHCI is probed first. > > > > > > > Is the current order just based on device init order? In my mind the > > > > expected behavior would be to always use USB 3.0 if it happens to be > > > > available in the hardware, specified in the DTS, enabled by the > > > > kernel configuration and firmware is loadable. Or does some case > > > > exist where it is better to use USB 2.0? I suspect no. > > > > > > I agree with you. > > > > > > > So I wonder if you have any plans how to make USB 3.0 enabled by > > > > default on Lager? > > > > > > It depends on a kernel config. I'm not sure of the shmobile_defconfig > > > strategy. But, in my opinion, one of a solution is kernel modules > > > (this means the "Case 2".) > > > > It sounds like we should enable CONFIG_EXTRA_FIRMWARE in shmobile_defconfig. I wonder what if any fallout we can foresee > > occurring if we do that. > > According to the firmware/README.AddingFirmware, we are unable to add a new firmware image to the firmware directory now. > So, if we enable CONFIG_EXTRA_FIRMWARE with the xHCI firmware, we will not build kernel because the xHCI firmware doesn't exist in the linux.git. > > === from firmware/README.AddingFirmware ===================================== > This directory is _NOT_ for adding arbitrary new firmware images. The > place to add those is the separate linux-firmware repository: > > git://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git > ============================================================================== Thanks. It seems that EXTRA_FIRMWARE is not an option from a mainline point of view after all. Is the problem in case 1 that the firmware can't be found because userspace does exist yet and thus can't be loaded from there? -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
