On 30.06.20 08:13, Oleksandr Andrushchenko wrote:
On 6/29/20 10:02 AM, Jürgen Groß wrote:
On 20.05.20 11:04, Oleksandr Andrushchenko wrote:
From: Oleksandr Andrushchenko <oleksandr_andrushche...@epam.com>

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_andrushche...@epam.com>
---
   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?

We can leave it as is, e.g. define XENDISPL_PROTOCOL_VERSION as "2",

so we do not break the existing users. Then if every user of the header has

its local copy (this is what we now use in the display backend), then that
local copy can be changed in a way suitable for the concrete user, e.g. "2"

redefined to 2. This cannot be done (?) for the Linux Kernel though.

Or we can have

#define XENDISPL_PROTOCOL_VERSION     "2"

#define XENDISPL_PROTOCOL_VERSION_INT  2

Jurgen, what's your preference here?

I would prefer the latter, as it avoids the need to modify the header
when copying it to a local project.


Juergen

Reply via email to