Re: [PATCH] USB: DWC3: Fix missed isoc IN transaction
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On 5/22/2012 12:57 AM, Paul Zimmerman wrote:
From: Pratyush Anand [mailto:pratyush.anand@xxxxxx] Sent: Monday, May 21, 2012 2:40 AM On 5/21/2012 2:46 PM, Felipe Balbi wrote:Hi, On Mon, May 21, 2012 at 02:41:13PM +0530, Pratyush Anand wrote:If I call dwc3_gadget_start_isoc_uf(dwc, dep, cur_uf) with cur_uf obtained from __dwc3_gadget_get_frame(dwc) , it does not work.I guess you have already this bug :-)even if we correct the mask, there would be issue. So frame number from DSTS is of 14 bits. Correct value of DSTS was 0x3C8FC. After correction of mask it will give uf as 0x391F which is not 0x791F coming from event->parameter.the missing bit on the mask fixes it, if you look at those numbers, 0x391f only missed bit 14, which was missing on your mask ;-)No.. to avoid confusion: At one instance: event->parameters is *0x791f*. DSTS is 0x3C8FC. Our mask is (0x3fff<< 3) = 0x1fff8 (0x3C8FC& 0x1fff8) = 0x1C8FC (0x1C8FC>> 3) = *0x391f* Also, since one has 16 bit space while other has 14 bit, so they can not be same always.Hi Pratyush, You should use the value from the event, not from DSTS. The extra bits in the event value take into account multiple frames.
But, if there is no way to get frame number other than xfernotready event->parameter, then I see one issue.
Consider a situation:-- Host wants to starts ISOC IN transfer. So it starts sending IN token or TP.
-- Since software has not configured TRB, so core will send 0 length packet.-- Lets say, gadget has not submitted any ep_queue. So even when xfernotready interrupt is received , any TRB will not be programmed.
-- Now, asynchronously gadget is ready and submits ep_queue. -- How will controller driver know that in which frame data has to be sent? Regards Pratyush -- 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
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