[PATCH 5 of 5] xen pvfb: Dynamic mode support (screen resizing)

From: Jeremy Fitzhardinge
Date: Fri May 23 2008 - 09:11:01 EST

From: Markus Armbruster <armbru@xxxxxxxxxx>

The pvfb backend indicates dynamic mode support by creating node
feature_resize with a non-zero value in its xenstore directory.
xen-fbfront sends a resize notification event on mode change. Fully
backwards compatible both ways.

Framebuffer size and initial resolution can be controlled through
kernel parameter xen_fbfront.video. The backend enforces a separate
size limit, which it advertises in node videoram in its xenstore
directory.

xen-kbdfront gets the maximum screen resolution from nodes width and
height in the backend's xenstore directory instead of hardcoding it.

Additional goodie: support for larger framebuffers (512M on a 64-bit
system with 4K pages).

Changing the number of bits per pixels dynamically is not supported,
yet.

Ported from
http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/92f7b3144f41
http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/bfc040135633

Signed-off-by: Pat Campbell <plc@xxxxxxxxxx>
Signed-off-by: Markus Armbruster <armbru@xxxxxxxxxx>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
---
drivers/input/xen-kbdfront.c | 10 ++
drivers/video/xen-fbfront.c | 183 ++++++++++++++++++++++++++++++++-------
include/xen/interface/io/fbif.h | 30 +++++-
3 files changed, 188 insertions(+), 35 deletions(-)

diff --git a/drivers/input/xen-kbdfront.c b/drivers/input/xen-kbdfront.c
--- a/drivers/input/xen-kbdfront.c
+++ b/drivers/input/xen-kbdfront.c
@@ -300,6 +300,16 @@
*/
if (dev->state != XenbusStateConnected)
goto InitWait; /* no InitWait seen yet, fudge it */
+
+ /* Set input abs params to match backend screen res */
+ if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+ "width", "%d", &val) > 0)
+ input_set_abs_params(info->ptr, ABS_X, 0, val, 0, 0);
+
+ if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+ "height", "%d", &val) > 0)
+ input_set_abs_params(info->ptr, ABS_Y, 0, val, 0, 0);
+
break;

case XenbusStateClosing:
diff --git a/drivers/video/xen-fbfront.c b/drivers/video/xen-fbfront.c
--- a/drivers/video/xen-fbfront.c
+++ b/drivers/video/xen-fbfront.c
@@ -43,23 +43,47 @@
struct xenfb_page *page;
unsigned long *mfns;
int update_wanted; /* XENFB_TYPE_UPDATE wanted */
+ int feature_resize; /* XENFB_TYPE_RESIZE ok */
+ struct xenfb_resize resize; /* protected by resize_lock */
+ int resize_dpy; /* ditto */
+ spinlock_t resize_lock;

struct xenbus_device *xbdev;
};

-static u32 xenfb_mem_len = XENFB_WIDTH * XENFB_HEIGHT * XENFB_DEPTH / 8;
+#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 };
+module_param_array(video, int, NULL, 0);
+MODULE_PARM_DESC(video,
+ "Video memory size in MB, width, height in pixels (default 2,800,600)");

static void xenfb_make_preferred_console(void);
static int xenfb_remove(struct xenbus_device *);
-static void xenfb_init_shared_page(struct xenfb_info *);
+static void xenfb_init_shared_page(struct xenfb_info *, struct fb_info *);
static int xenfb_connect_backend(struct xenbus_device *, struct xenfb_info *);
static void xenfb_disconnect_backend(struct xenfb_info *);
+
+static void xenfb_send_event(struct xenfb_info *info,
+ union xenfb_out_event *event)
+{
+ u32 prod;
+
+ prod = info->page->out_prod;
+ /* caller ensures !xenfb_queue_full() */
+ mb(); /* ensure ring space available */
+ XENFB_OUT_RING_REF(info->page, prod) = *event;
+ wmb(); /* ensure ring contents visible */
+ info->page->out_prod = prod + 1;
+
+ notify_remote_via_irq(info->irq);
+}

static void xenfb_do_update(struct xenfb_info *info,
int x, int y, int w, int h)
{
union xenfb_out_event event;
- u32 prod;

memset(&event, 0, sizeof(event));
event.type = XENFB_TYPE_UPDATE;
@@ -68,14 +92,19 @@
event.update.width = w;
event.update.height = h;

- prod = info->page->out_prod;
/* caller ensures !xenfb_queue_full() */
- mb(); /* ensure ring space available */
- XENFB_OUT_RING_REF(info->page, prod) = event;
- wmb(); /* ensure ring contents visible */
- info->page->out_prod = prod + 1;
+ xenfb_send_event(info, &event);
+}

- notify_remote_via_irq(info->irq);
+static void xenfb_do_resize(struct xenfb_info *info)
+{
+ union xenfb_out_event event;
+
+ memset(&event, 0, sizeof(event));
+ event.resize = info->resize;
+
+ /* caller ensures !xenfb_queue_full() */
+ xenfb_send_event(info, &event);
}

static int xenfb_queue_full(struct xenfb_info *info)
@@ -87,12 +116,28 @@
return prod - cons == XENFB_OUT_RING_LEN;
}

+static void xenfb_handle_resize_dpy(struct xenfb_info *info)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&info->resize_lock, flags);
+ if (info->resize_dpy) {
+ if (!xenfb_queue_full(info)) {
+ info->resize_dpy = 0;
+ xenfb_do_resize(info);
+ }
+ }
+ spin_unlock_irqrestore(&info->resize_lock, flags);
+}
+
static void xenfb_refresh(struct xenfb_info *info,
int x1, int y1, int w, int h)
{
unsigned long flags;
+ int x2 = x1 + w - 1;
int y2 = y1 + h - 1;
- int x2 = x1 + w - 1;
+
+ xenfb_handle_resize_dpy(info);

if (!info->update_wanted)
return;
@@ -225,6 +270,57 @@
return res;
}

+static int
+xenfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
+{
+ struct xenfb_info *xenfb_info;
+ int required_mem_len;
+
+ xenfb_info = info->par;
+
+ if (!xenfb_info->feature_resize) {
+ if (var->xres == video[KPARAM_WIDTH] &&
+ var->yres == video[KPARAM_HEIGHT] &&
+ var->bits_per_pixel == xenfb_info->page->depth) {
+ return 0;
+ }
+ return -EINVAL;
+ }
+
+ /* Can't resize past initial width and height */
+ if (var->xres > video[KPARAM_WIDTH] || var->yres > video[KPARAM_HEIGHT])
+ return -EINVAL;
+
+ required_mem_len = var->xres * var->yres * xenfb_info->page->depth / 8;
+ if (var->bits_per_pixel == xenfb_info->page->depth &&
+ var->xres <= info->fix.line_length / (XENFB_DEPTH / 8) &&
+ required_mem_len <= info->fix.smem_len) {
+ var->xres_virtual = var->xres;
+ var->yres_virtual = var->yres;
+ return 0;
+ }
+ return -EINVAL;
+}
+
+static int xenfb_set_par(struct fb_info *info)
+{
+ struct xenfb_info *xenfb_info;
+ unsigned long flags;
+
+ xenfb_info = info->par;
+
+ spin_lock_irqsave(&xenfb_info->resize_lock, flags);
+ xenfb_info->resize.type = XENFB_TYPE_RESIZE;
+ xenfb_info->resize.width = info->var.xres;
+ xenfb_info->resize.height = info->var.yres;
+ xenfb_info->resize.stride = info->fix.line_length;
+ xenfb_info->resize.depth = info->var.bits_per_pixel;
+ xenfb_info->resize.offset = 0;
+ xenfb_info->resize_dpy = 1;
+ spin_unlock_irqrestore(&xenfb_info->resize_lock, flags);
+ return 0;
+}
+
static struct fb_ops xenfb_fb_ops = {
.owner = THIS_MODULE,
.fb_read = fb_sys_read,
@@ -233,6 +329,8 @@
.fb_fillrect = xenfb_fillrect,
.fb_copyarea = xenfb_copyarea,
.fb_imageblit = xenfb_imageblit,
+ .fb_check_var = xenfb_check_var,
+ .fb_set_par = xenfb_set_par,
};

static irqreturn_t xenfb_event_handler(int rq, void *dev_id)
@@ -261,6 +359,8 @@
{
struct xenfb_info *info;
struct fb_info *fb_info;
+ int fb_size;
+ int val;
int ret;

info = kzalloc(sizeof(*info), GFP_KERNEL);
@@ -268,18 +368,35 @@
xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
return -ENOMEM;
}
+
+ /* 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])
+ video[KPARAM_MEM] = val;
+ }
+
+ /* 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) {
+ video[KPARAM_WIDTH] = XENFB_WIDTH;
+ video[KPARAM_HEIGHT] = XENFB_HEIGHT;
+ fb_size = XENFB_DEFAULT_FB_LEN;
+ }
+
dev->dev.driver_data = info;
info->xbdev = dev;
info->irq = -1;
info->x1 = info->y1 = INT_MAX;
spin_lock_init(&info->dirty_lock);
+ spin_lock_init(&info->resize_lock);

- info->fb = vmalloc(xenfb_mem_len);
+ info->fb = vmalloc(fb_size);
if (info->fb == NULL)
goto error_nomem;
- memset(info->fb, 0, xenfb_mem_len);
+ memset(info->fb, 0, fb_size);

- info->nr_pages = (xenfb_mem_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ info->nr_pages = (fb_size + PAGE_SIZE - 1) >> PAGE_SHIFT;

info->mfns = vmalloc(sizeof(unsigned long) * info->nr_pages);
if (!info->mfns)
@@ -289,8 +406,6 @@
info->page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
if (!info->page)
goto error_nomem;
-
- xenfb_init_shared_page(info);

/* abusing framebuffer_alloc() to allocate pseudo_palette */
fb_info = framebuffer_alloc(sizeof(u32) * 256, NULL);
@@ -304,9 +419,9 @@
fb_info->screen_base = info->fb;

fb_info->fbops = &xenfb_fb_ops;
- fb_info->var.xres_virtual = fb_info->var.xres = info->page->width;
- fb_info->var.yres_virtual = fb_info->var.yres = info->page->height;
- fb_info->var.bits_per_pixel = info->page->depth;
+ fb_info->var.xres_virtual = fb_info->var.xres = video[KPARAM_WIDTH];
+ fb_info->var.yres_virtual = fb_info->var.yres = video[KPARAM_HEIGHT];
+ fb_info->var.bits_per_pixel = XENFB_DEPTH;

fb_info->var.red = (struct fb_bitfield){16, 8, 0};
fb_info->var.green = (struct fb_bitfield){8, 8, 0};
@@ -318,9 +433,9 @@
fb_info->var.vmode = FB_VMODE_NONINTERLACED;

fb_info->fix.visual = FB_VISUAL_TRUECOLOR;
- fb_info->fix.line_length = info->page->line_length;
+ fb_info->fix.line_length = fb_info->var.xres * XENFB_DEPTH / 8;
fb_info->fix.smem_start = 0;
- fb_info->fix.smem_len = xenfb_mem_len;
+ fb_info->fix.smem_len = fb_size;
strcpy(fb_info->fix.id, "xen");
fb_info->fix.type = FB_TYPE_PACKED_PIXELS;
fb_info->fix.accel = FB_ACCEL_NONE;
@@ -336,6 +451,8 @@

fb_info->fbdefio = &xenfb_defio;
fb_deferred_io_init(fb_info);
+
+ xenfb_init_shared_page(info, fb_info);

ret = register_framebuffer(fb_info);
if (ret) {
@@ -389,7 +506,7 @@
struct xenfb_info *info = dev->dev.driver_data;

xenfb_disconnect_backend(info);
- xenfb_init_shared_page(info);
+ xenfb_init_shared_page(info, info->fb_info);
return xenfb_connect_backend(dev, info);
}

@@ -417,20 +534,23 @@
return pfn_to_mfn(vmalloc_to_pfn(address));
}

-static void xenfb_init_shared_page(struct xenfb_info *info)
+static void xenfb_init_shared_page(struct xenfb_info *info,
+ struct fb_info *fb_info)
{
int i;
+ int epd = PAGE_SIZE / sizeof(info->mfns[0]);

for (i = 0; i < info->nr_pages; i++)
info->mfns[i] = vmalloc_to_mfn(info->fb + i * PAGE_SIZE);

- info->page->pd[0] = vmalloc_to_mfn(info->mfns);
- info->page->pd[1] = 0;
- info->page->width = XENFB_WIDTH;
- info->page->height = XENFB_HEIGHT;
- info->page->depth = XENFB_DEPTH;
- info->page->line_length = (info->page->depth / 8) * info->page->width;
- info->page->mem_length = xenfb_mem_len;
+ for (i = 0; i * epd < info->nr_pages; i++)
+ info->page->pd[i] = vmalloc_to_mfn(&info->mfns[i * epd]);
+
+ info->page->width = fb_info->var.xres;
+ info->page->height = fb_info->var.yres;
+ info->page->depth = fb_info->var.bits_per_pixel;
+ info->page->line_length = fb_info->fix.line_length;
+ info->page->mem_length = fb_info->fix.smem_len;
info->page->in_cons = info->page->in_prod = 0;
info->page->out_cons = info->page->out_prod = 0;
}
@@ -530,6 +650,11 @@
val = 0;
if (val)
info->update_wanted = 1;
+
+ if (xenbus_scanf(XBT_NIL, dev->otherend,
+ "feature-resize", "%d", &val) < 0)
+ val = 0;
+ info->feature_resize = val;
break;

case XenbusStateClosing:
diff --git a/include/xen/interface/io/fbif.h b/include/xen/interface/io/fbif.h
--- a/include/xen/interface/io/fbif.h
+++ b/include/xen/interface/io/fbif.h
@@ -49,11 +49,27 @@
int32_t height; /* rect height */
};

+/*
+ * Framebuffer resize notification event
+ * Capable backend sets feature-resize in xenstore.
+ */
+#define XENFB_TYPE_RESIZE 3
+
+struct xenfb_resize {
+ uint8_t type; /* XENFB_TYPE_RESIZE */
+ int32_t width; /* width in pixels */
+ int32_t height; /* height in pixels */
+ int32_t stride; /* stride in bytes */
+ int32_t depth; /* depth in bits */
+ int32_t offset; /* start offset within framebuffer */
+};
+
#define XENFB_OUT_EVENT_SIZE 40

union xenfb_out_event {
uint8_t type;
struct xenfb_update update;
+ struct xenfb_resize resize;
char pad[XENFB_OUT_EVENT_SIZE];
};

@@ -105,15 +121,18 @@
* Each directory page holds PAGE_SIZE / sizeof(*pd)
* framebuffer pages, and can thus map up to PAGE_SIZE *
* PAGE_SIZE / sizeof(*pd) bytes. With PAGE_SIZE == 4096 and
- * sizeof(unsigned long) == 4, that's 4 Megs. Two directory
- * pages should be enough for a while.
+ * sizeof(unsigned long) == 4/8, that's 4 Megs 32 bit and 2
+ * Megs 64 bit. 256 directories give enough room for a 512
+ * Meg framebuffer with a max resolution of 12,800x10,240.
+ * Should be enough for a while with room leftover for
+ * expansion.
*/
- unsigned long pd[2];
+ unsigned long pd[256];
};

/*
- * Wart: xenkbd needs to know resolution. Put it here until a better
- * solution is found, but don't leak it to the backend.
+ * Wart: xenkbd needs to know default resolution. Put it here until a
+ * better solution is found, but don't leak it to the backend.
*/
#ifdef __KERNEL__
#define XENFB_WIDTH 800


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