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SubjectRe: [RESEND/PATCH 5/6] USB: musb-gadget: complete request only if data is transfered over
Hello.

Felipe Balbi wrote:

>> If a DMA interrupt comes when the whole transfer is not yet
>> complete (and
>> other Ming Lei's patches are making this possible),

Oh, here I mixed some other patch with Ming Lei's ones...

>> it will pass due to the

> than this is the actual problem, no ? If we're using mode1 dma (as we
> are on tx path), we should only get dma interrupt when the whole
> transfer has been completed.

The Inventra DMA controller has serious DMA length limitation, so the whole
transfer may take more than one DMA.

>> 'ís_dma' condition above the patched code:

>> if (is_dma || request->actual == request->length) {

>> and then it will hit the code sending the final ZLP (above this
>> patched code too):

> but this was already there before the patch.

Yes, and here lies the problem.

>> /*
>> * First, maybe a terminating short packet.
>> Some DMA
>> * engines might handle this by themselves.
>> */
>> if ((request->zero && request->length
>> && request->length %
>> musb_ep->packet_sz == 0)
>> #ifdef CONFIG_USB_INVENTRA_DMA
>> || (is_dma && (!dma->desired_mode ||
>> (request->actual &
>> (musb_ep->packet_sz -
>> 1))))
>> #endif
>> ) {

>> before the transfer is complete while it should only be hit when and
>> only when
>> the whole transfer is complete. The current code doesn't look correct
>> as well
>> though, all due to this 'ís_dma' condition. Surely this needs fixing.

> likewise, this was there before the patch. I don't think the real
> problem lies with this patch, it's been there for a while, don't you
> agree ?

Then what problem this patch fixes, if not this one?

> the problem is not on the extra if () added below the quoted code,
> it's on the quoted code itself, which wasn't changed in any way.

Let me repeat: in the PIO mode the added check is just duplicate, in the DMA
mode it's added too late in the code, after ZLP/short packet send is triggered.
We should modify the check at the top of that code instead.

WBR, Sergei
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