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[203.10.76.45]) by mx.google.com with ESMTPS id eh5si1090075pac.347.2013.05.14.22.21.00 for (version=TLSv1.2 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 14 May 2013 22:21:01 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of rusty@ozlabs.org designates 203.10.76.45 as permitted sender) client-ip=203.10.76.45; Received: by ozlabs.org (Postfix, from userid 1011) id D95112C00B7; Wed, 15 May 2013 15:20:58 +1000 (EST) From: Rusty Russell To: Pranavkumar Sawargaonkar Cc: "linux-arm-kernel\@lists.infradead.org" , "kvmarm\@lists.cs.columbia.edu" , "linux-kernel\@vger.kernel.org" , "linaro-kernel\@lists.linaro.org" , Patch Tracking , Anup Patel , Amit Shah Subject: Re: [PATCH V2 2/3] Documentation: virtio: Add emergency write (emerg_wr) config register in virtio console. In-Reply-To: References: <1367842791-30285-1-git-send-email-pranavkumar@linaro.org> <1367842791-30285-3-git-send-email-pranavkumar@linaro.org> <8761yn382w.fsf@rustcorp.com.au> User-Agent: Notmuch/0.15.2+81~gd2c8818 (http://notmuchmail.org) Emacs/23.4.1 (i686-pc-linux-gnu) Date: Wed, 15 May 2013 13:59:29 +0930 Message-ID: <87hai427di.fsf@rustcorp.com.au> MIME-Version: 1.0 X-Gm-Message-State: ALoCoQlzTZUUVmYYa+42pcEQYvCLq8kjxMETFHxE9Rhvu/1oZX0rP77dhkRUdjhSVVoxblcoTCuU X-Original-Sender: rusty@rustcorp.com.au X-Original-Authentication-Results: mx.google.com; spf=neutral (google.com: 2607:f8b0:400c:c01::22d is neither permitted nor denied by best guess record for domain of patch+caf_=patchwork-forward=linaro.org@linaro.org) smtp.mail=patch+caf_=patchwork-forward=linaro.org@linaro.org Precedence: list Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org List-ID: X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , Pranavkumar Sawargaonkar writes: > Hi Rusty, > > On 13 May 2013 08:22, Rusty Russell wrote: >> Pranavkumar Sawargaonkar writes: >>> Signed-off-by: Pranavkumar Sawargaonkar >>> Signed-off-by: Anup Patel >>> --- >>> Documentation/virtual/virtio-spec.txt | 8 +++++++- >>> 1 file changed, 7 insertions(+), 1 deletion(-) >> >> OK, I applied this to the lyx master, with three changes: >> 1) Changed "filed" to "field". >> 2) Added ", or even acknowledging the feature" after "without >> initializing virtio queues". >> 3) Added an initial point to the Device Initialization section: >> >> 1. If the VIRTIO_CONSOLE_F_EMERG_WRITE feature is offered, the >> emerg_wr field of the configuration can be written at any time. Thus >> it should work for very early boot debugging output as well as >> catastophic OS failures (eg. virtio ring corruption). > > Thanks for applying this patch. > Have you also applied first patch ([PATCH V2 1/3] virtio: console: Add > emergency writeonly register to config space) > with this? (https://lkml.org/lkml/2013/5/6/169) Would like Amit's Ack, since he's de-facto console maintainer. I've reproduced it below. Cheers, Rusty. Subject: [PATCH V2 1/3] virtio: console: Add emergency writeonly register to config space Date: Mon, 6 May 2013 17:49:49 +0530 Message-Id: <1367842791-30285-2-git-send-email-pranavkumar@linaro.org> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1367842791-30285-1-git-send-email-pranavkumar@linaro.org> References: <1367842791-30285-1-git-send-email-pranavkumar@linaro.org> X-Gm-Message-State: ALoCoQmDOoCdPmDpT+VgLwYAlJHmkUTB8sEAHVSbrNxWBzYgPHFT9rQ2A9dR8fToM81cHDZDppGx This patch adds an emerg_wr register (writeonly) in config space of virtio console device which can be used for debugging. Signed-off-by: Pranavkumar Sawargaonkar Signed-off-by: Anup Patel Signed-off-by: Rusty Russell --- include/uapi/linux/virtio_console.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/uapi/linux/virtio_console.h b/include/uapi/linux/virtio_console.h index ee13ab6..3fd0dce 100644 --- a/include/uapi/linux/virtio_console.h +++ b/include/uapi/linux/virtio_console.h @@ -38,6 +38,7 @@ /* Feature bits */ #define VIRTIO_CONSOLE_F_SIZE 0 /* Does host provide console size? */ #define VIRTIO_CONSOLE_F_MULTIPORT 1 /* Does host provide multiple ports? */ +#define VIRTIO_CONSOLE_F_EMERG_WRITE 2 /* Does host support emergency write? */ #define VIRTIO_CONSOLE_BAD_ID (~(u32)0) @@ -48,6 +49,8 @@ struct virtio_console_config { __u16 rows; /* max. number of ports this device can hold */ __u32 max_nr_ports; + /* emergency write register */ + __u32 emerg_wr; } __attribute__((packed)); /*