[Qemu-devel] [PATCH] hw/qxl: allow vram to be sized to 4096 bytes

[Qemu-devel] [PATCH] hw/qxl: allow vram to be sized to 4096 bytes

[Alon Levy]

This allows us to reduce the size of the surfaces bar minimally while
not breaking current drivers. To completely disable the bar, or make it
zero sized, would break them.

Signed-off-by: Alon Levy <alevy@redhat.com>
---
 hw/qxl.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/hw/qxl.c b/hw/qxl.c
index ac69125..b1a2daa 100644
--- a/hw/qxl.c
+++ b/hw/qxl.c
@@ -1556,10 +1556,12 @@ static int qxl_init_common(PCIQXLDevice *qxl)
     init_qxl_rom(qxl);
     init_qxl_ram(qxl);
 
-    if (qxl->vram_size < 16 * 1024 * 1024) {
+    /* a request of 0 vram_size is translated to the smallest vram that doesn't
+     * break current off screen surfaces using drivers */
+    if (qxl->vram_size > 0 && qxl->vram_size < 16 * 1024 * 1024) {
         qxl->vram_size = 16 * 1024 * 1024;
     }
-    if (qxl->revision == 1) {
+    if (qxl->revision == 1 || qxl->vram_size == 0) {
         qxl->vram_size = 4096;
     }
     qxl->vram_size = msb_mask(qxl->vram_size * 2 - 1);
-- 
1.7.9

Re: [Qemu-devel] [PATCH] hw/qxl: allow vram to be sized to 4096 bytes

[Gerd Hoffmann]

  Hi,

> -    if (qxl->vram_size < 16 * 1024 * 1024) {
> +    /* a request of 0 vram_size is translated to the smallest vram that doesn't
> +     * break current off screen surfaces using drivers */
> +    if (qxl->vram_size > 0 && qxl->vram_size < 16 * 1024 * 1024) {

Is there any reason to keep the 16MB minimum size?  I think we can just
drop it and simplify the logic here.  See the patch series just sent.

cheers,
  Gerd

Re: [Qemu-devel] [PATCH] hw/qxl: allow vram to be sized to 4096 bytes

[Alon Levy]

On Fri, Feb 17, 2012 at 04:11:59PM +0100, Gerd Hoffmann wrote:
>   Hi,
> 
> > -    if (qxl->vram_size < 16 * 1024 * 1024) {
> > +    /* a request of 0 vram_size is translated to the smallest vram that doesn't
> > +     * break current off screen surfaces using drivers */
> > +    if (qxl->vram_size > 0 && qxl->vram_size < 16 * 1024 * 1024) {
> 
> Is there any reason to keep the 16MB minimum size?  I think we can just
> drop it and simplify the logic here.  See the patch series just sent.

I agree. Will review your patchset.

> 
> cheers,
>   Gerd
> 

[Qemu-devel] [PATCH] hw/qxl: allow vram to be sized to 4096 bytes

[Alon Levy]

This allows us to reduce the size of the surfaces bar minimally while
not breaking current drivers. To completely disable the bar, or make it
zero sized, would break them.

Signed-off-by: Alon Levy <alevy@redhat.com>
---
Causes endless ooms for the linux driver, but it's mainly meant for the
windows driver, where it was tested (with a previous patch I can't find,
but this one is simple enough and equivalent).

 hw/qxl.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/hw/qxl.c b/hw/qxl.c
index 41500e9..592842b 100644
--- a/hw/qxl.c
+++ b/hw/qxl.c
@@ -1559,10 +1559,12 @@ static int qxl_init_common(PCIQXLDevice *qxl)
     init_qxl_rom(qxl);
     init_qxl_ram(qxl);
 
-    if (qxl->vram_size < 16 * 1024 * 1024) {
+    /* a request of 0 vram_size is translated to the smallest vram that doesn't
+     * break current off screen surfaces using drivers */
+    if (qxl->vram_size > 0 && qxl->vram_size < 16 * 1024 * 1024) {
         qxl->vram_size = 16 * 1024 * 1024;
     }
-    if (qxl->revision == 1) {
+    if (qxl->revision == 1 || qxl->vram_size == 0) {
         qxl->vram_size = 4096;
     }
     qxl->vram_size = msb_mask(qxl->vram_size * 2 - 1);
-- 
1.7.7.1