[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]
Subject: [PATCH RESEND] Documentation: virtio: Add emergency write (emerg_wr) config register in virtio console.
This patch updates virtio spec lyx for adding emergency write to virtio console. Original patch series related to this is -: http://lkml.org/lkml/2013/5/6/167 Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org> Signed-off-by: Anup Patel <anup.patel@linaro.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> --- diff --git a/virtio-spec.lyx b/virtio-spec.lyx index 73e22e7..adec0a5 100644 --- a/virtio-spec.lyx +++ b/virtio-spec.lyx @@ -6835,6 +6835,17 @@ VIRTIO_CONSOLE_F_SIZE VIRTIO_CONSOLE_F_MULTIPORT(1) Device has support for multiple ports; configurati on fields nr_ports and max_nr_ports are valid and control virtqueues will be used. +\change_inserted 1112500848 1368412890 + +\end_layout + +\begin_layout Description + +\change_inserted 1112500848 1368412929 +VIRTIO_CONSOLE_F_EMERG_WRITE(2) Device has support for emergency write. + Configuration field emerg_wr is valid. +\change_unchanged + \end_layout \end_deeper @@ -6851,6 +6862,14 @@ layout The size of the console is supplied in the configuration space if the VIRTIO_CONSOLE_F_SIZE feature is set. Furthermore, if the VIRTIO_CONSOLE_F_MULTIPORT feature is set, the maximum number of ports supported by the device can be fetched. + +\change_inserted 1112500848 1368412999 + If VIRTIO_CONSOLE_F_EMERG_WRITE is set then one can use emergency write + to output single character without initializing virtio queues, or even + acknowledging the feature. + +\change_unchanged + \begin_inset listings inline false status open @@ -6877,6 +6896,17 @@ struct virtio_console_config { \begin_layout Plain Layout u32 max_nr_ports; +\change_inserted 1112500848 1368413026 + +\end_layout + +\begin_layout Plain Layout + +\change_inserted 1112500848 1368413032 + + u32 emerg_wr; +\change_unchanged + \end_layout \begin_layout Plain Layout @@ -6894,6 +6924,16 @@ Device Initialization \end_layout \begin_layout Enumerate + +\change_inserted 1112500848 1368413220 +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). +\end_layout + +\begin_layout Enumerate If the VIRTIO_CONSOLE_F_SIZE feature is negotiated, the driver can read the console dimensions from the configuration fields. \end_layout
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]