From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tim Nordell Subject: Re: DM3730 + MUSB host mode + DMA + USB Ethernet dongle = Fail Date: Thu, 07 May 2015 16:26:16 -0500 Message-ID: <554BD878.7090907@logicpd.com> References: <554AA11B.9040909@logicpd.com> <20150507160606.GB15563@atomide.com> <20150507161656.GB29183@saruman.tx.rr.com> <554BAC48.2050406@logicpd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-omap@vger.kernel.org Hi Felipe - On 05/07/15 16:21, Bin Liu wrote: >> I'm sorry if you are already aware of this information. >> Just wanted to share my experience. >> >> AFAIK, there is a hardware bug with MUSB Host controller. >> See ARM_MPU.KERNEL.39 at >> http://processors.wiki.ti.com/index.php/Sitara_SDK_6.00.00_Release_Notes >> I assume it is common across AM335x and DM3730. > > No, it is not. One thing I just found errata advisory 1.81 for the DM37x indicating that "USB OTG DMA May Stall Under Specific Configuration". Does the MUSB driver account for this advisory? If not, maybe all DMA requests for the MUSB port could be queued for the DM37x so that they're guaranteed to be one at a time? If double buffering enabled in the FIFO, it should permit fast bursts of data in and out of the MUSB driver. - Tim -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html