From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55408) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1euN4j-0006wS-Ig for qemu-devel@nongnu.org; Fri, 09 Mar 2018 13:49:06 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1euN4i-0003x2-Kk for qemu-devel@nongnu.org; Fri, 09 Mar 2018 13:49:05 -0500 Received: from mail-ot0-x243.google.com ([2607:f8b0:4003:c0f::243]:40852) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1euN4i-0003wu-Ft for qemu-devel@nongnu.org; Fri, 09 Mar 2018 13:49:04 -0500 Received: by mail-ot0-x243.google.com with SMTP id l12so9583181otj.7 for ; Fri, 09 Mar 2018 10:49:04 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20180309182030.GA22836@roeck-us.net> References: <1520444223-8389-1-git-send-email-linux@roeck-us.net> <20180308171239.GA22206@roeck-us.net> <201803081028.39635.wpaul@windriver.com> <20180309182030.GA22836@roeck-us.net> From: Peter Maydell Date: Fri, 9 Mar 2018 18:48:43 +0000 Message-ID: Content-Type: text/plain; charset="UTF-8" Subject: Re: [Qemu-devel] [PATCH] fsl-imx6: Swap Ethernet interrupt defines List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Guenter Roeck Cc: Bill Paul , QEMU Developers , Andrey Smirnov , Chris Healy , Jason Wang , Jean-Christophe Dubois On 9 March 2018 at 18:20, Guenter Roeck wrote: > On Fri, Mar 09, 2018 at 05:47:16PM +0000, Peter Maydell wrote: >> Thanks for that really useful writeup. So if I understand correctly >> we have several choices here: >> >> (1) we could implement a model of the IOMUX block that is at least >> sufficient to support guests that configure it to route the ENET interrupt >> line to a GPIO pin. Then we could apply this patch that fixes the ENET >> line definitions. Old kernels would continue to work (for the same >> reason they worked on hardware), and new ones would work now too. >> This is in some ways the preferred option, but it's possibly a lot >> of code and we're nearly in freeze for 2.12. >> >> (2) we could leave everything as it is for 2.12. This would mean that >> at least we don't regress setups that used to work on older QEMU versions. >> Downside is that we wouldn't be able to run Linux v4.15+, or other >> guest OSes that don't have the bug that older Linux kernels do. >> (Presumably we'd only do this on the understanding that we were going >> to go down route (1) for 2.13.) >> >> (3) we could apply this patch for 2.12. Linux v4.15+ now works, as >> do other guest OSes that use the ENET interrupt. v4.1 and older Linux >> guests that used to boot in QEMU stop doing so, and 4.2-4.9 boot but >> lose the ethernet device support. Perhaps for 2.13 we might >> take route (1) to make those older guests start working again. >> >> Do I have that right? >> > Pretty much. > >> None of these options seems especially palatable to me, so we're >> choosing the lesser evil, I think... (unless somebody wants to say >> that option (1) would be 20 lines of code and here's the patch :-)) >> I guess in the absence of (1) that (3) is better than (2) ? >> > > I would prefer (2). This is what I decided to use in my "local" > version of qemu. Older versions of Linux can be fixed by applying one > (4.2..4.9) or two (4.1 and older) upstream patches; anyone interested > running those kernels in qemu with Ethernet working should apply those > patches (or, alternatively, provide a patch adding IOMUX support to > qemu). Did you mean "prefer (3) [apply this patch]" ? The rest of the paragraph makes more sense if you did. thanks -- PMM