From: Doug Anderson <dianders@chromium.org>
To: Kever Yang <kever.yang@rock-chips.com>
Cc: "John Youn" <John.Youn@synopsys.com>,
"Felipe Balbi" <balbi@ti.com>,
"Tao Huang" <huangtao@rock-chips.com>,
"Herrero, Gregory" <gregory.herrero@intel.com>,
"Heiko Stübner" <heiko@sntech.de>,
"John Youn" <johnyoun@synopsys.com>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Ming Lei" <ming.lei@canonical.com>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"open list:ARM/Rockchip SoC..."
<linux-rockchip@lists.infradead.org>,
"Kaukab, Yousaf" <yousaf.kaukab@intel.com>,
"Alan Stern" <stern@rowland.harvard.edu>,
吴良峰 <william.wu@rock-chips.com>,
"Julius Werner" <jwerner@chromium.org>,
"Dinh Nguyen" <dinguyen@opensource.altera.com>
Subject: Re: [PATCH v5 04/21] usb: dwc2: host: Set host_perio_tx_fifo_size to 304 for rk3066
Date: Thu, 28 Jan 2016 15:25:35 -0800 [thread overview]
Message-ID: <CAD=FV=UQF7u1t79Aac0Y70eYERuhg4dS-ciof9KpqFTL+EYujQ@mail.gmail.com> (raw)
In-Reply-To: <CAD=FV=Xtbmf2yOQx=cNTnrsV_35jTUhJCKbBNuHCRpr-qXrW0A@mail.gmail.com>
Hi,
On Thu, Jan 28, 2016 at 10:16 AM, Doug Anderson <dianders@chromium.org> wrote:
> Kever,
>
>
> On Wed, Jan 27, 2016 at 10:41 PM, Kever Yang <kever.yang@rock-chips.com> wrote:
>> Hi Doug,
>>
>> We are in HOST mode, we only need to receive data from USB camera
>> with RX FIFO, and no need to use TX FIFO for USB webcam, right? :)
>>
>> Any way, I think we need to NAK this patch after look into the design
>> of dwc2 controller. Because all the dwc2 controller inside the Rockchip
>> chips don't support the thresholding FIFO mode, in this case, there is
>> no more transaction before a whole packet is send out and the dwc2 only
>> care if the available FIFO is enough for next packet or not.
>>
>> So, the addition 48 words won't help to shorten the latency for data prepare
>> in this case.
>
> Ah ha! I see where I messed up. It wasn't lack of FIFO space that I
> was running into, it was lack of queue space. :-P I had conflated
> the two of them in my mind. We still use the TX queue to transmit
> small packets so that we can receive our data...
>
> OK, so it's pretty sane to assume that exhausting the periodic TX FIFO
> isn't terribly common, I think. Audio won't do it by itself and you
> probably won't have more than one audio device. I guess if you had a
> video _output_ device hooked over USB then it could possible exhaust
> things. ...but I think dwc2 still has a ways to do before I'd suggest
> anyone hooking that up. :-P At some point in time you could imagine
> the driver being more dynamic.
>
> OK, so the non periodic FIFO it is, then.
Actually, in my simple tests adding it to the non periodic FIFO didn't
help at all. I'll just drop this patch.
-Doug
next prev parent reply other threads:[~2016-01-28 23:25 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-22 18:18 [PATCH v5 0/21] usb: dwc2: host: Fix and speed up all the stuff, especially with splits Douglas Anderson
2016-01-22 18:18 ` [PATCH v5 01/21] usb: dwc2: rockchip: Make the max_transfer_size automatic Douglas Anderson
2016-01-22 18:18 ` [PATCH v5 02/21] usb: dwc2: host: Get aligned DMA in a more supported way Douglas Anderson
2016-01-22 18:18 ` [PATCH v5 03/21] usb: dwc2: host: Set host_rx_fifo_size to 528 for rk3066 Douglas Anderson
2016-01-27 10:13 ` Kever Yang
2016-01-27 19:44 ` Doug Anderson
2016-01-28 8:28 ` Kever Yang
2016-01-22 18:18 ` [PATCH v5 04/21] usb: dwc2: host: Set host_perio_tx_fifo_size to 304 " Douglas Anderson
2016-01-28 3:10 ` Kever Yang
2016-01-28 3:28 ` Doug Anderson
2016-01-28 6:41 ` Kever Yang
2016-01-28 18:16 ` Doug Anderson
2016-01-28 23:25 ` Doug Anderson [this message]
2016-01-22 18:18 ` [PATCH v5 05/21] usb: dwc2: host: Avoid use of chan->qh after qh freed Douglas Anderson
2016-01-28 3:25 ` Kever Yang
2016-01-28 23:26 ` Doug Anderson
2016-01-22 18:18 ` [PATCH v5 06/21] usb: dwc2: host: Always add to the tail of queues Douglas Anderson
2016-01-27 10:23 ` Kever Yang
2016-01-22 18:18 ` [PATCH v5 07/21] usb: dwc2: hcd: fix split transfer schedule sequence Douglas Anderson
2016-01-28 1:20 ` Kever Yang
2016-01-22 18:18 ` [PATCH v5 08/21] usb: dwc2: host: Add scheduler tracing Douglas Anderson
2016-01-28 3:39 ` Kever Yang
2016-01-22 18:18 ` [PATCH v5 09/21] usb: dwc2: host: Add a delay before releasing periodic bandwidth Douglas Anderson
2016-01-22 18:18 ` [PATCH v5 10/21] usb: dwc2: host: Giveback URB in tasklet context Douglas Anderson
2016-01-22 18:18 ` [PATCH v5 11/21] usb: dwc2: host: Use periodic interrupt even with DMA Douglas Anderson
2016-01-22 18:18 ` [PATCH v5 12/21] usb: dwc2: host: Rename some fields in struct dwc2_qh Douglas Anderson
2016-01-22 18:18 ` [PATCH v5 13/21] usb: dwc2: host: Reorder things in hcd_queue.c Douglas Anderson
2016-01-22 18:18 ` [PATCH v5 14/21] usb: dwc2: host: Split code out to make dwc2_do_reserve() Douglas Anderson
2016-01-22 18:18 ` [PATCH v5 15/21] usb: dwc2: host: Add scheduler logging for missed SOFs Douglas Anderson
2016-01-22 18:18 ` [PATCH v5 16/21] usb: dwc2: host: Manage frame nums better in scheduler Douglas Anderson
2016-01-27 20:49 ` Doug Anderson
2016-01-22 18:18 ` [PATCH v5 17/21] usb: dwc2: host: Schedule periodic right away if it's time Douglas Anderson
2016-01-22 18:18 ` [PATCH v5 18/21] usb: dwc2: host: Add dwc2_hcd_get_future_frame_number() call Douglas Anderson
2016-01-22 18:18 ` [PATCH v5 19/21] usb: dwc2: host: Properly set even/odd frame Douglas Anderson
2016-01-22 18:18 ` [PATCH v5 20/21] usb: dwc2: host: Totally redo the microframe scheduler Douglas Anderson
2016-01-24 5:44 ` Doug Anderson
2016-01-22 18:18 ` [PATCH v5 21/21] usb: dwc2: host: If using uframe scheduler, end splits better Douglas Anderson
2016-01-23 17:52 ` [PATCH v5 0/21] usb: dwc2: host: Fix and speed up all the stuff, especially with splits Heiko Stuebner
2016-01-23 23:09 ` Doug Anderson
2016-01-24 5:36 ` Doug Anderson
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