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Re: [PATCH] usb: gadget: f_midi: Add checking if it need align buffer's size to an ep's maxpacketsize

From Michal Nazarewicz <mina86@mina86.com>
Newsgroups linux.kernel
Subject Re: [PATCH] usb: gadget: f_midi: Add checking if it need align buffer's size to an ep's maxpacketsize
Date 2016-07-08 16:10 +0200
Message-ID <rSEDE-5P7-33@gated-at.bofh.it> (permalink)
References <rSdDr-4Xv-7@gated-at.bofh.it> <rSE0V-5l8-11@gated-at.bofh.it>
Organization http://mina86.com/

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> Baolin Wang <baolin.wang@linaro.org> writes:
>> @@ -359,10 +361,12 @@ static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
>>  
>>  	/* allocate a bunch of read buffers and queue them all at once. */
>>  	for (i = 0; i < midi->qlen && err == 0; i++) {
>> -		struct usb_request *req =
>> -			midi_alloc_ep_req(midi->out_ep,
>> -				max_t(unsigned, midi->buflen,
>> -					bulk_out_desc.wMaxPacketSize));
>> +		struct usb_request *req;
>> +
>> +		length = usb_ep_align_maybe(midi->gadget, midi->out_ep,
>> +					    midi->buflen);

On Fri, Jul 08 2016, Felipe Balbi wrote:
> after calling usb_ep_align_maybe()...
>
>> +		req = midi_alloc_ep_req(midi->out_ep,
>> +			max_t(unsigned, length, bulk_out_desc.wMaxPacketSize));
>
> ... max_t() is pointless. length will *always* >= wMaxPacketSize.

That is only true for gadgets with the quirk.  usb_ep_align_maybe is
a noöp for gadgets without the quirk.

-- 
Best regards
ミハウ “𝓶𝓲𝓷𝓪86” ナザレヴイツ
«If at first you don’t succeed, give up skydiving»

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[PATCH] usb: gadget: f_midi: Add checking if it need align buffer's size to an ep's maxpacketsize Baolin Wang <baolin.wang@linaro.org> - 2016-07-07 11:20 +0200
  Re: [PATCH] usb: gadget: f_midi: Add checking if it need align buffer's size to an ep's maxpacketsize Michal Nazarewicz <mina86@mina86.com> - 2016-07-07 15:00 +0200
    Re: [PATCH] usb: gadget: f_midi: Add checking if it need align  buffer's size to an ep's maxpacketsize Baolin Wang <baolin.wang@linaro.org> - 2016-07-08 04:30 +0200
      Re: [PATCH] usb: gadget: f_midi: Add checking if it need align buffer's size to an ep's maxpacketsize Michal Nazarewicz <mina86@mina86.com> - 2016-07-08 15:10 +0200
        Re: [PATCH] usb: gadget: f_midi: Add checking if it need align buffer's size to an ep's maxpacketsize Felipe Balbi <balbi@kernel.org> - 2016-07-08 15:30 +0200
        Re: [PATCH] usb: gadget: f_midi: Add checking if it need align buffer's size to an ep's maxpacketsize Felipe Balbi <balbi@kernel.org> - 2016-07-08 15:30 +0200
          Re: [PATCH] usb: gadget: f_midi: Add checking if it need align buffer's size to an ep's maxpacketsize Michal Nazarewicz <mina86@mina86.com> - 2016-07-08 16:10 +0200
  Re: [PATCH] usb: gadget: f_midi: Add checking if it need align buffer's size to an ep's maxpacketsize Felipe Balbi <balbi@kernel.org> - 2016-07-08 15:30 +0200
    Re: [PATCH] usb: gadget: f_midi: Add checking if it need align buffer's size to an ep's maxpacketsize Michal Nazarewicz <mina86@mina86.com> - 2016-07-08 16:10 +0200

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