On 11/28/2016 07:15 AM, Dongwoo Lee wrote: > On 11/26/2016 03:25 AM, Marek Vasut wrote: >> On 11/22/2016 03:42 AM, Dongwoo Lee wrote: >>> On 2016년 11월 18일 23:01, Marek Vasut wrote: >>>> On 11/18/2016 08:24 AM, Jaehoon Chung wrote: >>>>> Hi, >>>>> >>>>> Added Marek as USB maintainer. >>>>> >>>>> On 11/17/2016 01:21 PM, Dongwoo Lee wrote: >>>>>> The transfer request exceeding 4032KB (the maximum number of TRBs per >>>>>> TD * the maximum size of transfer buffer on TRB) fails on xhci host >>>>>> with timed out error or babble error state. This failure occurs when >>>>>> accessing large files on USB mass-storage. Currently with xhci as well >>>>>> as ehci host, the driver requests maximum 30MB (65536 blks * 512 byte) >>>>>> to storage at once. However, xhci cannot handle this request because >>>>>> of the reason mentioned above, even though ehci can handle this. Thus, >>>>>> transfer request larger than this size should be splitted in order to >>>>>> limit the length of data in a single TD. >>>>>> >>>>>> Even though the single request is splitted into multiple requests, >>>>>> the transfer speed has affected insignificantly in comparison with >>>>>> ehci host: 22.6 MB/s on ehci and 22.3 MB/s on xhci for 100MB tranfer. >>>>> >>>>> I don't have USB knowledge..So i wonder that this is correct way. >>>>> Have other guys ever seen the similar issue? >>>> >>>> Is this a controller limitation ? >>>> >>>> btw can you fix your mailer to NOT send HTML email to the list? >>>> >>> >>> If my understanding for xhci spec.(rev. 1.1) 4.9.2 is right, the controller >>> has no limitation for transfer size because it can support a very large TRB >>> ring with multiple Ring Segments. >>> >>> However, the xhci driver seems not to be implemented for supporting it; >>> the TRB ring is comprised of only a single segment. As a result, it cannot >>> handle the request exceeding 4032KB (TRB_MAX_BUFF_SIZE(64KB) * >>> (TRBS_PER_SEGMENT(64) - link TRB(1)), thus the request should be divided. >> >> Can we update the driver ? >> > > Yes, I agree. > I think also updating driver is more reasonable. > > Though I think it takes some time since I just started xhci, I will > prepare a patch for enabling multiple ring segments for the driver.
Great, thanks! -- Best regards, Marek Vasut _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
