From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fgw23-7.mail.saunalahti.fi (fgw23-7.mail.saunalahti.fi [62.142.5.84]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BEC33156966 for ; Wed, 3 Apr 2024 22:26:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.142.5.84 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712183172; cv=none; b=QzSNR6CWfQQbBbXqu2eCEMJboEGbWY1VytBHEYbW37VjJFbo9qTEGRRfzC8/e8AJe4bd43yJXB23h2cCfEysiw5bvi6l17TUrhpDyfkkzJnqTTL/tIMT55CbwtLGDX8NxWwOnjDNQHP3JSzdNP3Aj3IQtt4RAOP3XEQB++z+jIM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712183172; c=relaxed/simple; bh=s207HgJoe5eibYyo9LW5tjcHICxSNKnKZt+o0hm3+lw=; h=From:Date:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=P3uJpS57z+0uf+q6joC0/lNbHqVLAswd7W6NBK7+UHyBT3uFJ4CphWnlQDl2jpWgIAHEd647TqHy4s9guwfXKL5bnLmSz6LLmcTVPnQ9/Yo6ZIEgsNLHnTdNwO8unaxg2WXGYqvbJXMZysU0JbaiFZGY2qgOdnY/UHD4r5Gvi00= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com; spf=fail smtp.mailfrom=gmail.com; arc=none smtp.client-ip=62.142.5.84 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=gmail.com Received: from localhost (88-113-26-217.elisa-laajakaista.fi [88.113.26.217]) by fgw23.mail.saunalahti.fi (Halon) with ESMTP id 2abd16a8-f209-11ee-b972-005056bdfda7; Thu, 04 Apr 2024 01:26:08 +0300 (EEST) From: Andy Shevchenko Date: Thu, 4 Apr 2024 01:26:07 +0300 To: Joshua Droney Cc: Greg KH , linux-serial@vger.kernel.org Subject: Re: Incorrect UART in /tty/serial/8250 Message-ID: References: <2024032920-replay-ruined-d92d@gregkh> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Fri, Mar 29, 2024 at 09:23:49AM -0500, Joshua Droney kirjoitti: First of all, do not top-post in the Linux kernel related mailing lists. > I would appreciate some guidance on this. I don't know enough about > the kernel's serial driver to be confident about what changes need to > be made, nor anything about creating/submitting a patch. You may start from here: https://www.kernel.org/doc/html/latest/process/submitting-patches.html https://www.kernel.org/doc/html/latest/process/submit-checklist.html > On Fri, Mar 29, 2024 at 1:01 AM Greg KH wrote: > > > > On Thu, Mar 28, 2024 at 02:34:10PM -0500, Joshua Droney wrote: > > > Hello! > > > > > > My name is Josh. I'm currently employed at Commtech, Inc. > > > (https://fastcomproducts.com/). I'm following the instructions at > > > https://kernelnewbies.org/FoundBug to report this issue. Please let me > > > know if this is incorrect. > > > > > > We (Commtech) have several serial boards, but the board in question is > > > the '422/2-PCIe'. This board does not exist, but someone added it to > > > the Linux kernel at some point in the past. This wouldn't be a > > > problem, except that the board ID that was used for this non-existent > > > board (0x22) was ultimately used for a different REAL board, with a > > > different UART. Instead of a xr172358, we use a 16C950 on the real > > > board. But the Linux kernel finds our other board ID, and tries to > > > initialize it as an exar chip and fails. I don't know much about the > > > kernel, but I believe the lines in question are: > > > > > > https://github.com/torvalds/linux/blob/master/drivers/tty/serial/8250/8250_exar.c#L47 > > > https://github.com/torvalds/linux/blob/master/drivers/tty/serial/8250/8250_exar.c#L925 > > > > > > You can see that we have a different board with device ID 0x22 here: > > > https://admin.pci-ids.ucw.cz/read/PC/18f7 > > > > > > The 422/4-PCIe exists (0x20), the 422/8-PCIe exists (0x21), but the > > > 422/2-PCIe was never created and its device id was used for a > > > different board (0x22, the SuperFSCC/4-LVDS-PCIe). > > > > Can you please submit a patch that fixes this? We'll be glad to take > > it. If you need help making it, please let us know. -- With Best Regards, Andy Shevchenko