From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: [V2,1/5] usb: serial: f81534: add high baud rate support From: Johan Hovold Message-Id: <20180110084914.GV11344@localhost> Date: Wed, 10 Jan 2018 09:49:14 +0100 To: "Ji-Ze Hong \(Peter Hong\)" Cc: Johan Hovold , gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, peter_hong@fintek.com.tw, "Ji-Ze Hong \(Peter Hong\)" List-ID: T24gV2VkLCBKYW4gMTAsIDIwMTggYXQgMDE6MzA6MThQTSArMDgwMCwgSmktWmUgSG9uZyAoUGV0 ZXIgSG9uZykgd3JvdGU6Cj4gSGkgSm9oYW4sCj4gCj4gSm9oYW4gSG92b2xkIOaWvCAyMDE4LzEv OSDkuIvljYggMDc6MDgg5a+r6YGTOgo+ID4gT24gVGh1LCBKYW4gMDQsIDIwMTggYXQgMTA6Mjk6 MTdBTSArMDgwMCwgSmktWmUgSG9uZyAoUGV0ZXIgSG9uZykgd3JvdGU6Cj4gPj4gVGhlIEY4MTUz Mi81MzQgaGFkIDQgY2xvY2tzb3VyY2UgMS44NDYvMTguNDYvMTQuNzcvMjRNSHogYW5kIGJhdWQg cmF0ZXMKPiA+PiBjYW4gYmUgdXAgdG8gMS41TWJpdHMgd2l0aCAyNE1Iei4KPiA+Pgo+ID4+IFRo aXMgZGV2aWNlIG1heSBnZW5lcmF0ZSBkYXRhIG92ZXJydW4gd2hlbiBiYXVkIHJhdGUgc2V0dGlu ZyB0byA5MjE2MDBicHMKPiA+PiBvciBoaWdoZXIgd2l0aCBvbGQgVUFSVCB0cmlnZ2VyIGxldmVs IHNldHRpbmcgKDh4MTQ9MTEyKSB3aXRoIGZ1bGwKPiA+PiBsb2FkaW5nLiBXZSdsbCBjaGFuZ2Ug dHJpZ2dlciBsZXZlbCBmcm9tIDh4MTQ9MTEyIHRvIDh4OD02NCB0byBhdm9pZCBkYXRhCj4gPj4g b3ZlcnJ1bi4KPiA+Pgo+ID4+IEFsc28gdGhlIHJlYWQvd3JpdGUgb2YgRVAwIHdpbGwgYmUgYWZm ZWN0ZWQgYnkgdGhpcyBwYXRjaC4gVGhlIHdvcnN0IGNhc2UKPiA+PiBvZiByZXNwb25kaW5nIHRp bWUgaXMgMjBzIHdoZW4gYWxsIHNlcmlhbCBwb3J0IGFyZSBmdWxsIGxvYWRpbmcgYW5kIHRyeWlu Zwo+ID4+IHRvIGFjY2VzcyBFUDAsIHNvIHdlIGNoYW5nZSBFUDAgdGltZW91dCBmcm9tIDEwIHRv IDIwcy4KPiA+IAo+ID4gU3VyZWx5IHlvdSBtZWFudCAxIGFuZCAyIHNlY29uZHMgcmVzcGVjdGl2 ZWx5IGhlcmU/IEFuZCBpZiB5b3UgaGF2ZQo+ID4gaW5kZWVkIG1lYXN1cmVkIHJlc3BvbnNlIHRp bWVzIGNsb3NlIHRvIDIwMDAgbXMgdGhlbiBwZXJoYXBzIHlvdSB3YW50IHRvCj4gPiBhZGQgZXZl biBtb3JlIG1hcmdpbj8KPiAKPiBOb3JtYWxseSwgdGhlIGNvbW11bmljYXRpb24gd2l0aCBGODE1 MzQgZXAwIHdpbGwgdGFrZSBsZXNzIHRoYW4gMSBzZWMKPiAoZXZlbiBvbmx5IHNvbWUgbWlsbGlz ZWNvbmRzKSwgYnV0IEl0IG1heWJlIHRha2UgbXVjaCBsb25nIHRpbWUgd2l0aAo+IGh1Z2UgbG9h ZGluZyB3aXRoIFVBUlQgZnVuY3Rpb25hbC4KPiAKPiBXZSBoYWQgdGVzdGVkIGl0IG9uIEJ1cm5J blRlc3QsIDQgcG9ydHMgd2l0aCA5MjE2MDBicHMgKyBNU1Igc3RhdHVzCj4gY2hlY2sgdG8gcGVy Zm9ybSBodWdlIGxvYWRpbmcgdGVzdC4gVGhlIHdvcnN0IGNhc2UgdG8gcmVhZCBNU1IgcmVnaXN0 ZXIKPiB2aWEgZXAwIHdpbGwgdGFrZSAxNX4xOCBzZWNvbmRzLiBTbyBXZSdsbCBzdGlsbCByZW1h aW4gdGhlIG1heCB3YWl0aW5nCj4gdGltZSBmb3IgYWNjZXNzIGVwMCB3aXRoIDJ4MTA9MjBzIGlu IGhpZ2ggYmF1ZCByYXRlIG1vZGUuCgpXb3csIHRoYXQncyB1bmZvcnR1bmF0ZS4gQnV0IG5vdGUg dGhhdCB5b3VyIHBhdGNoIG9ubHkgZG91YmxlcyB0aGUKdGltZW91dCB0byAyMDAwIG1zLCB0aGF0 IGlzLCB0d28gc2Vjb25kcyBhbmQgbm90IHR3ZW50eToKCi0jZGVmaW5lIEY4MTUzNF9VU0JfVElN RU9VVCAgICAgICAgICAgICAxMDAwCisjZGVmaW5lIEY4MTUzNF9VU0JfVElNRU9VVCAgICAgICAg ICAgICAyMDAwCgpJZiB5b3UgcmVhbGx5IGludGVuZGVkIHRvIGluY3JlYXNlIHRoaXMgdG8gdHdl bnR5IHNlY29uZHMsIHRoZW4gcGxlYXNlCmRvIHNvIGluIGEgc2VwYXJhdGUgKHByZXBhcmF0b3J5 KSBwYXRjaCB3aGVyZSB5b3UgZGVzY3JpYmUgd2h5IHRoYXQgaXMKbmVlZGVkIChlLmcuIHdoYXQg eW91IHdyb3RlIGFib3ZlKS4KCkpvaGFuCi0tLQpUbyB1bnN1YnNjcmliZSBmcm9tIHRoaXMgbGlz dDogc2VuZCB0aGUgbGluZSAidW5zdWJzY3JpYmUgbGludXgtdXNiIiBpbgp0aGUgYm9keSBvZiBh IG1lc3NhZ2UgdG8gbWFqb3Jkb21vQHZnZXIua2VybmVsLm9yZwpNb3JlIG1ham9yZG9tbyBpbmZv IGF0ICBodHRwOi8vdmdlci5rZXJuZWwub3JnL21ham9yZG9tby1pbmZvLmh0bWwK From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934181AbeAJItV (ORCPT + 1 other); Wed, 10 Jan 2018 03:49:21 -0500 Received: from mail-lf0-f42.google.com ([209.85.215.42]:38469 "EHLO mail-lf0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753056AbeAJItS (ORCPT ); Wed, 10 Jan 2018 03:49:18 -0500 X-Google-Smtp-Source: ACJfBouBNpq9EVdReY/I+1zEZ3JEkE8//hKgbEAjwRKViTENyHhpHf4cQJ2Nx1JQpM8txoA3pkdkkQ== Date: Wed, 10 Jan 2018 09:49:14 +0100 From: Johan Hovold To: "Ji-Ze Hong (Peter Hong)" Cc: Johan Hovold , gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, peter_hong@fintek.com.tw, "Ji-Ze Hong (Peter Hong)" Subject: Re: [PATCH V2 1/5] usb: serial: f81534: add high baud rate support Message-ID: <20180110084914.GV11344@localhost> References: <1515032961-29131-1-git-send-email-hpeter+linux_kernel@gmail.com> <20180109110841.GN11344@localhost> <18d4171a-1e1a-5476-dc9d-02a522cbf077@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <18d4171a-1e1a-5476-dc9d-02a522cbf077@gmail.com> User-Agent: Mutt/1.7.2 (2016-11-26) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Wed, Jan 10, 2018 at 01:30:18PM +0800, Ji-Ze Hong (Peter Hong) wrote: > Hi Johan, > > Johan Hovold 於 2018/1/9 下午 07:08 寫道: > > On Thu, Jan 04, 2018 at 10:29:17AM +0800, Ji-Ze Hong (Peter Hong) wrote: > >> The F81532/534 had 4 clocksource 1.846/18.46/14.77/24MHz and baud rates > >> can be up to 1.5Mbits with 24MHz. > >> > >> This device may generate data overrun when baud rate setting to 921600bps > >> or higher with old UART trigger level setting (8x14=112) with full > >> loading. We'll change trigger level from 8x14=112 to 8x8=64 to avoid data > >> overrun. > >> > >> Also the read/write of EP0 will be affected by this patch. The worst case > >> of responding time is 20s when all serial port are full loading and trying > >> to access EP0, so we change EP0 timeout from 10 to 20s. > > > > Surely you meant 1 and 2 seconds respectively here? And if you have > > indeed measured response times close to 2000 ms then perhaps you want to > > add even more margin? > > Normally, the communication with F81534 ep0 will take less than 1 sec > (even only some milliseconds), but It maybe take much long time with > huge loading with UART functional. > > We had tested it on BurnInTest, 4 ports with 921600bps + MSR status > check to perform huge loading test. The worst case to read MSR register > via ep0 will take 15~18 seconds. So We'll still remain the max waiting > time for access ep0 with 2x10=20s in high baud rate mode. Wow, that's unfortunate. But note that your patch only doubles the timeout to 2000 ms, that is, two seconds and not twenty: -#define F81534_USB_TIMEOUT 1000 +#define F81534_USB_TIMEOUT 2000 If you really intended to increase this to twenty seconds, then please do so in a separate (preparatory) patch where you describe why that is needed (e.g. what you wrote above). Johan