[Xen-devel] [PATCH 1/3] xen-fbfront: Read width/height from backend

[Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>]

This allows the backend driver to specify the size of the framebuffer
instead of requiring it to be on the kernel command line.

Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
---
 drivers/video/xen-fbfront.c |   30 ++++++++++++++++++++++++------
 1 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/drivers/video/xen-fbfront.c b/drivers/video/xen-fbfront.c
index a20218c..56d6061 100644
--- a/drivers/video/xen-fbfront.c
+++ b/drivers/video/xen-fbfront.c
@@ -58,7 +58,7 @@ struct xenfb_info {
 #define XENFB_DEFAULT_FB_LEN (XENFB_WIDTH * XENFB_HEIGHT * XENFB_DEPTH / 8)
 
 enum { KPARAM_MEM, KPARAM_WIDTH, KPARAM_HEIGHT, KPARAM_CNT };
-static int video[KPARAM_CNT] = { 2, XENFB_WIDTH, XENFB_HEIGHT };
+static int video[KPARAM_CNT] = { 0, 0, 0 };
 module_param_array(video, int, NULL, 0);
 MODULE_PARM_DESC(video,
        "Video memory size in MB, width, height in pixels (default 2,800,600)");
@@ -363,7 +363,7 @@ static int __devinit xenfb_probe(struct xenbus_device *dev,
 {
        struct xenfb_info *info;
        struct fb_info *fb_info;
-       int fb_size;
+       int fb_size, fb_need;
        int val;
        int ret;
 
@@ -375,14 +375,32 @@ static int __devinit xenfb_probe(struct xenbus_device 
*dev,
 
        /* Limit kernel param videoram amount to what is in xenstore */
        if (xenbus_scanf(XBT_NIL, dev->otherend, "videoram", "%d", &val) == 1) {
-               if (val < video[KPARAM_MEM])
+               if (!video[KPARAM_MEM] || val < video[KPARAM_MEM])
                        video[KPARAM_MEM] = val;
        }
 
+       /* Take width/height from xenstore if not set on command line */
+       if (!video[KPARAM_WIDTH]) {
+               if (xenbus_scanf(XBT_NIL, dev->otherend, "width", "%d", &val) 
== 1)
+                       video[KPARAM_WIDTH] = val;
+               else
+                       video[KPARAM_WIDTH] = XENFB_WIDTH;
+       }
+       if (!video[KPARAM_HEIGHT]) {
+               if (xenbus_scanf(XBT_NIL, dev->otherend, "height", "%d", &val) 
== 1)
+                       video[KPARAM_HEIGHT] = val;
+               else
+                       video[KPARAM_HEIGHT] = XENFB_HEIGHT;
+       }
+
+       fb_need = video[KPARAM_WIDTH] * video[KPARAM_HEIGHT] * XENFB_DEPTH / 8;
+       if (video[KPARAM_MEM])
+               fb_size = video[KPARAM_MEM] * 1024 * 1024;
+       else
+               fb_size = video[KPARAM_MEM] = fb_need;
+
        /* If requested res does not fit in available memory, use default */
-       fb_size = video[KPARAM_MEM] * 1024 * 1024;
-       if (video[KPARAM_WIDTH] * video[KPARAM_HEIGHT] * XENFB_DEPTH / 8
-           > fb_size) {
+       if (fb_need > fb_size) {
                video[KPARAM_WIDTH] = XENFB_WIDTH;
                video[KPARAM_HEIGHT] = XENFB_HEIGHT;
                fb_size = XENFB_DEFAULT_FB_LEN;
-- 
1.7.3.4


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