From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BFEECC47404 for ; Sun, 6 Oct 2019 01:24:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 91718222CD for ; Sun, 6 Oct 2019 01:24:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="RRVGuTVM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727085AbfJFBYL (ORCPT ); Sat, 5 Oct 2019 21:24:11 -0400 Received: from mail-io1-f66.google.com ([209.85.166.66]:44290 "EHLO mail-io1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726967AbfJFBYL (ORCPT ); Sat, 5 Oct 2019 21:24:11 -0400 Received: by mail-io1-f66.google.com with SMTP id w12so21344446iol.11; Sat, 05 Oct 2019 18:24:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=BpwjrntPw3QU5FS5zxzc856KaCEN2bZjIDxTo2gPBTI=; b=RRVGuTVM2GwvaR1hmZcWUeSBKJB3KaJS6S79PeDQXG/8Nfs/c4GqCRX/DGvYGh5LrB XmgsgB413q2z6i76U4GfCD7d8/ZNfm3CSdKxWZvou8d9E8WbRUm4q7NhVpJldg+VNBai oVNJ3e34QTyJ6iub1S5OJgGqaHOvyowjT5Ea39GTNKuB4vTjsE342LiwFK86Kcfio/xn bsyYIRhE6PeUVdsbsN9j6d7ai123g6n0r/1J6duWKhW9dGI3UuwqGgi3hnJbiSvoB3Er 1kR5RbfcQ9e7xZz3Tnh8oY+7e9k1bmw9pXNepkhCh+K88kXwbWoxHwLBt8eA7PTXYz3Z 8WGQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=BpwjrntPw3QU5FS5zxzc856KaCEN2bZjIDxTo2gPBTI=; b=a6CCdNwudX9+ADvi/7FL3VsF8PiYRrkJvPCsw/9Y+i/8FHuW7iHW5InmhbqL/p/bNx WA2RkZCXMYhSOh5bu6mX22hLV2t0sE2hCR0SHxItHo1zUrYw3MS40IcAWOPjOkDbgFvn nDcn6FtJIxPZnD/6Mh0RPP3ROpajLOuED2hjzNYG16sulQnVgn7E7EGH841cww9akt1/ i6IU3NjFZCxtUtNBmiarBY4Kl1wXvUZNHBjSFXjEl05b5t/GTO0sVDDhnQIuGXL0Bim3 IX3ENe4mJMjFdWouXbqQTN8w5nB/qPSeE4mCuTpw2D+9kvAnWOtTYU99mgOedbPT5E/E CpMA== X-Gm-Message-State: APjAAAW+a6Ipv75Q/wx+QmJpjVGmCe7ccpSDRWWJIJT0MMmGKdiSQmdI FofPRWsuRd7/tOLiDT5Jv2nPWCkCLQ+mS8ec6wY= X-Google-Smtp-Source: APXvYqy1npk0qb6meNa3A8CMFIFHvlHQ9ynrzU9CXUMnJ4XIuQC2emAHkjlKKzgyWn/kSY0UQqvGu8PVHMeMca8KASw= X-Received: by 2002:a92:3f0a:: with SMTP id m10mr22411122ila.158.1570325049820; Sat, 05 Oct 2019 18:24:09 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Adam Ford Date: Sat, 5 Oct 2019 20:23:58 -0500 Message-ID: Subject: Re: DM3730 Bluetooth Performance differences between SERIAL_8250_OMAP vs SERIAL_OMAP To: Yegor Yefremov Cc: Greg Kroah-Hartman , Jiri Slaby , linux-serial@vger.kernel.org, Linux Kernel Mailing List , Linux-OMAP , Vignesh R Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 4, 2019 at 10:45 PM Adam Ford wrote: > > On Fri, Oct 4, 2019 at 11:51 AM Adam Ford wrote: > > > > On Fri, Oct 4, 2019 at 9:08 AM Adam Ford wrote: > > > > > > On Fri, Oct 4, 2019 at 7:27 AM Yegor Yefremov > > > wrote: > > > > > > > > Hi Adam, > > > > > > > > On Fri, Oct 4, 2019 at 12:39 PM Adam Ford wrote: > > > > > > > > > > On Fri, Oct 4, 2019 at 5:02 AM Adam Ford wrote: > > > > > > > > > > > > I am running Kernel 5.3.2 trying to troubleshoot some intermittent > > > > > > Bluetooth issues, and I think I have narrowed it down to the serial > > > > > > driver in use. > > > > > > > > > > I should have also noted that it's using UART2 with CTS and RTS on the > > > > > DM3730 (omap3630) and its configured with a baud rate of 3M. > > > > > I tried slowing it to 115200, but that didn't help. I tried disabling > > > > > the DMA hooks from the device tree, and that didn't help. > > > > > > > > > > > By default, omap2plus_defconfig enables both SERIAL_8250_OMAP and > > > > > > SERIAL_OMAP. I have my console device configured as ttyS0, and all > > > > > > appears fine. When I enable Bluetooth, however, I get intermittent > > > > > > errors on an DM3730 / OMAP3630. > > > > > > > > > > > > Using the 8250 driver for Blueotooth I get intermittent frame errors > > > > > > and data loss. > > > > > > > > > > > > Scanning ... > > > > > > [ 28.482452] Bluetooth: hci0: Frame reassembly failed (-84) > > > > > > [ 36.162170] Bluetooth: hci0: Frame reassembly failed (-84) > > > > > > F4:4E:FC:C9:2F:57 BluJax > > > > > > # l2ping F4:4E:FC:C9:2F:57 > > > > > > Ping: F4:4E:FC:C9:2F:57 from 00:18:30:49:7D:63 (data size 44) ... > > > > > > 44 bytes from F4:4E:FC:C9:2F:57 id 0 time 8.27ms > > > > > > no response from F4:4E:FC:C9:2F:57: id 1 > > > > > > ^C2 sent, 1 received, 50% loss > > > > > > > > > > > > (after a fairly long hang, I hit control-c) > > > > > > > > > > > > However, disabling the 8250 driver and using the only SERIAL_OMAP and > > > > > > the console routed to ttyO0, the Bluetooth works well, so I believe it > > > > > > to be a serial driver issue and not a Bluetooth error. > > > > > > > > > > > > # hcitool scan > > > > > > Scanning ... > > > > > > F4:4E:FC:C9:2F:57 BluJax > > > > > > ^C > > > > > > # l2ping F4:4E:FC:C9:2F:57 > > > > > > Ping: F4:4E:FC:C9:2F:57 from 00:18:30:49:7D:63 (data size 44) ... > > > > > > 44 bytes from F4:4E:FC:C9:2F:57 id 0 time 6.90ms > > > > > > ... > > > > > > 44 bytes from F4:4E:FC:C9:2F:57 id 14 time 28.29ms > > > > > > ^C15 sent, 15 received, 0% loss > > > > > > # > > > > > > > > > > > > 0% loss and regular, repeatable communication without any Frame > > > > > > reassembly errors. > > > > > > > > > > > > > > > > I tried disabling SERIAL_OMAP and using only SERIAL_8250_OMAP, but > > > > > that didn't help. Because the issue goes away when I disable > > > > > SERIAL_8250_OMAP, I am wondering if something is either being > > > > > misconfigured or some IRQ or DMA integration is missing that may be > > > > > present with the older SERIAL_OMAP driver. > > > > > > > > > > > Any suggestions on how to troubleshoot or what might cause the > > > > > > difference between the two drivers? > > > > > > > > Can it be related to this issue [1]? Can you confirm that 5.2 is > > > > working as expected with the 8250 driver? > > > > > > > > [1] https://marc.info/?l=linux-serial&m=156965039008649&w=2 > > > > > > I reverted the whole 8250 directory to d99482673f95 ("serial: > > > mctrl_gpio: Check if GPIO property exisits before requesting it") and > > > it is somewhat better, but it's not as good as the stock OMAP serial > > > driver. I get some frame errors and eventually, I get some timeouts, > > > but it's not as bad. I'll try to implement the RTS and CTS as gpio > > > pins and change the device tree accordingly. It might shed some light > > > on the situation. > > > > I tried to manually setup RTS and CTS pins as GPIO, but that didn't > > work, so I changed it back. > > > > It looks like the clocking is correct. I don't know enough about the > > DMA or the IRQ to know if it's working correctly. > > > > I was wondering if the problem is in the handshaking or not. > > I added " uart-has-rtscts;" to by uart node thinking it might help, > > but it did not. > > > > > > > 8250_omap.c has some checks to see if we can enable autoRTS: > > > > if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW && > > !up->gpios) { > > /* Enable AUTOCTS (autoRTS is enabled when RTS is raised) */ > > ... > > } > > > > Based on this, I would expect up->gpios to always be zero if we want > > auto RTS CTS. > > > > I threw some debug code into the serial driver to look at the status > > of the various flags that go into setting up auto RTS/CTS. > > > > [ 13.837005] termios->c_cflag & CRTSCTS = 80000000 > > [ 13.841888] up->port.flags & UPF_HARD_FLOW = 300000 > > [ 13.846801] up->gpios = ce3f3cc0 > > [ 17.166595] termios->c_cflag & CRTSCTS = 0 > > [ 17.170745] up->port.flags & UPF_HARD_FLOW = 300000 > > [ 17.175781] up->gpios = ce3f3d40 > > > > I don't know which port is which, but I only have two active uarts > > (console and Bluetooth) > > The Bluetooth port should use handshaking and the console should not. > > > > From the look of the dump, up->gpios is never 0, so the last > > evaluation would always be false unless I am misinterpreting > > something. > > > > I tried to modify the check to remove !up->gpios check, but that > > didn't help either, but it made it a little better. > > I have it working now on the 5.3.y branch, but I had to do 4 things. > > 1) Disable the older OMAP serial driver > 2) Apply [1] patch > 3) Disable 8250 DMA support > 4) Remove checks for !up->gpios in the 8250-omap.c code. > > With all those changes, I am able to successfully and repeatedly scan > and l2ping Bluetooth devices. Without any one of those, I get frame > errors or lost packets. > > I wonder if we can dump the legacy omap serial driver once the 8250 > driver is working better. That would eliminate at least one of the 4. > I am not sure what's up with the DMA, and I've already stated some > thoughts on item 4 in a previous e-mail. > > I think the [1] patch is probably going to help fix some other issues > and should probably be backported, but by itself it isn't enough to > fix the Bluetooth problem on the OMAP3630. > > [1] - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/tty/serial/8250/8250_omap.c?h=v5.4-rc1&id=627a545c6bb0c7de09208e6546f5111290477261 > In the latest 'master' branch of 5.4-RC1 (43b815c6a8e7), I have confirmed that by removing the DMA and forcing the checks for !up->gpios to be true to keep the hardware flow control working, I can repeatably make Bluetooth work. I am not sure what's broken in the DMA, but the check for !up->gpios is never false, so it never actually does the code inside to address handshaking index c68e2b3a1634..884fcba61303 100644 --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -141,7 +141,7 @@ static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) serial8250_do_set_mctrl(port, mctrl); - if (!up->gpios) { + if (1 /* !up->gpios */) { /* * Turn off autoRTS if RTS is lowered and restore autoRTS * setting if RTS is raised @@ -455,8 +455,7 @@ static void omap_8250_set_termios(struct uart_port *port, priv->efr = 0; up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF); - if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW && - !up->gpios) { + if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW) { /* Enable AUTOCTS (autoRTS is enabled when RTS is raised) */ up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS; priv->efr |= UART_EFR_CTS; I know this is wrong to do what I did, but whatever is setting gpios is clearly not setting it to NULL, so I am guessing these checks here to be something else or something needs to be able to set these to NULL when there are no manually configured gpio pints for cts/rts. adam > adam > > > > > > > adam > > > > > > > > Cheers, > > > > Yegor