Re: [PATCH 1/2] xen/displif: Protocol version 2

[Jürgen Groß <jgross@xxxxxxxx>]

On 20.05.20 11:04, Oleksandr Andrushchenko wrote:
> From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
>
> 1. Change protocol version from string to integer
>
> Version string, which is in fact an integer, is hard to handle in the
> code that supports different protocol versions. To simplify that
> make the version an integer.
>
> 2. Pass buffer offset with XENDISPL_OP_DBUF_CREATE
>
> There are cases when display data buffer is created with non-zero
> offset to the data start. Handle such cases and provide that offset
> while creating a display buffer.
>
> 3. Add XENDISPL_OP_GET_EDID command
>
> Add an optional request for reading Extended Display Identification
> Data (EDID) structure which allows better configuration of the
> display connectors over the configuration set in XenStore.
> With this change connectors may have multiple resolutions defined
> with respect to detailed timing definitions and additional properties
> normally provided by displays.
>
> If this request is not supported by the backend then visible area
> is defined by the relevant XenStore's "resolution" property.
>
> If backend provides extended display identification data (EDID) with
> XENDISPL_OP_GET_EDID request then EDID values must take precedence
> over the resolutions defined in XenStore.
>
> 4. Bump protocol version to 2.
>
> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
> ---
>   xen/include/public/io/displif.h | 83 +++++++++++++++++++++++++++++++--
>   1 file changed, 80 insertions(+), 3 deletions(-)
>
> diff --git a/xen/include/public/io/displif.h b/xen/include/public/io/displif.h
> index cc5de9cb1f35..4d43ba5078c8 100644
> --- a/xen/include/public/io/displif.h
> +++ b/xen/include/public/io/displif.h
> @@ -38,7 +38,7 @@
>    *                           Protocol version
>    
> ******************************************************************************
>    */
> -#define XENDISPL_PROTOCOL_VERSION     "1"
> +#define XENDISPL_PROTOCOL_VERSION     2
This is not very nice regarding compatibility.

Can't you add a new macro for the integer value?

And please add comments further down which additions are related to
the new version.


Juergen