From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753193AbaC3KRU (ORCPT ); Sun, 30 Mar 2014 06:17:20 -0400 Received: from mail-ve0-f173.google.com ([209.85.128.173]:48047 "EHLO mail-ve0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751570AbaC3KRS convert rfc822-to-8bit (ORCPT ); Sun, 30 Mar 2014 06:17:18 -0400 MIME-Version: 1.0 In-Reply-To: <20140323193839.GY15608@titan.lakedaemon.net> References: <1395093587-2583-1-git-send-email-teobaluta@gmail.com> <20140319201838.GA11403@redhat.com> <20140321132816.GW15608@titan.lakedaemon.net> <532DC3D3.9060008@linux.com> <20140323193839.GY15608@titan.lakedaemon.net> Date: Sun, 30 Mar 2014 12:17:17 +0200 X-Google-Sender-Auth: XD69p3i05UR4H3Nw2civXV9fRgA Message-ID: Subject: Re: [RFC] QR encoding for Oops messages From: Levente Kurusa To: Jason Cooper , =?ISO-8859-2?B?VGVvZG9yYSBC42x1/uM=?= Cc: Dave Jones , "linux-kernel@vger.kernel.org" , "Waskiewicz Jr, Peter P" Content-Type: text/plain; charset=ISO-8859-2 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi all, (sorry for the late reply, looks like this mail has ran away from my clients) 2014-03-23 20:38 GMT+01:00 Jason Cooper : > All, > > On Sat, Mar 22, 2014 at 08:20:01PM +0200, Teodora Băluță wrote: >> On Sat, Mar 22, 2014 at 7:09 PM, Levente Kurusa wrote: >> > On 03/21/2014 02:28 PM, Jason Cooper wrote: > ... >> >> I would definitely like to see the QR output incorporated into a >> >> kernel.org url. That would remove the need for installing another app, >> >> and would ease bug reporting. >> > >> > I still struggle to understand how could that be done. We can encode the >> > QR code as ASCII. Okay, that's fine, however it is very long. Encoding >> > 'Unable to handle kernel paging request at 0000000f' gave a 449 character >> > long sequence with very strange characters [0]. We should try to shorten >> > it, imho. Not sure how to do that though. > > The man page for qrencode says you can have up to 4000 characters in a > qrcode. However, I've seen readers have trouble with a 2048bit ascii > armored PGP public key (3929 characters). > > I grabbed a random oops from oops.kernel.org, it weighed in at 1544 > bytes, not too bad. I then did: > > $ echo "https://oops.kernel.org/?qr=`cat oops.txt | gzip -9 | base64 -wrap=0`" | wc -c > 993 I did the same with another OOPS and it had 1953 characters. That's quite a big a big difference! :-) I created a QR image from the URL then, and it was 147x147, which is pretty small. It took me quite a long time to make my phone recognize it, but it worked nicely. Result of work is in this directory: http://levex.fedorapeople.org/kernel/qr/ > > The benefit of a url is that any QR reader can automagically report an > oops. While a specific app could parse the URL/oops locally if the > user desires. > >> it misses the point of having a QR code in the first place. The way I >> see it, having a QR decoder app installed that can do an offline >> decoding is a less greater effort than popping out a browser on the >> machine you're working on. > > I think you're selling the advantage of the QR code short. Automated > reporting (via the url) is a _huge_ plus. The app you conceive of could > still parse it in place if the user desires. > > My point for the URL isn't to use the internet/server to automate oops > parsing for the user. Rather it's to make it easy to report oopses to > developers. While still preserving the ability of your app to parse it > for the user. Ah I see now. oops.kernel.org/?qr= would simply parse the base64'd+gzip'd oops message and then report it. Now I guess we need to think how to make it work without a framebuffer. I already suggested using the ASCII characters, but seeing the resolution of this QR code for example (147x147), made me realize that we can't shuffle that into a 80x25 textmode display. Any ideas how to fix that or should we just simply depend on a framebuffer being present? -- Regards, Levente Kurusa