Re: [Qemu-devel] [RFC PATCH] vga: Start supporting resolution not multiple of 16 correctly.

[Fabio Fantoni]

Il 18/06/2013 12:17, Frediano Ziglio ha scritto:

Modern notebook support 1366x768 resolution. The resolution width is
not multiple of 16 causing some problems.

QEMU VGA emulation requires width resolution to be multiple of 8.

VNC implementation requires width resolution to be multiple of 16.

Signed-off-by: Frediano Ziglio <address@hidden>

Tested-by: Fabio Fantoni <address@hidden>

I tested it for a long time with spice on xen (because qxl will be fully working only after adding SSE support on hvm domUs). It works, I think it is good to add this and the respective vgabios patch on upstream.

---
 hw/display/vga.c |    2 +-
 ui/vnc.c         |   34 +++++++++++++++++++---------------
 2 files changed, 20 insertions(+), 16 deletions(-)

Updates:

- rebased

- fixed style problems

- fixed typos in comment

Attached patch for last vgabios in order to get some new resolutions.

Still had no time to test deeply.

diff --git a/hw/display/vga.c b/hw/display/vga.c
index 21a108d..0053b0f 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -648,7 +648,7 @@ void vbe_ioport_write_data(void *opaque, uint32_t addr, uint32_t val)
             }
             break;
         case VBE_DISPI_INDEX_XRES:
-            if ((val <= VBE_DISPI_MAX_XRES) && ((val & 7) == 0)) {
+            if ((val <= VBE_DISPI_MAX_XRES) && ((val & 1) == 0)) {
                 s->vbe_regs[s->vbe_index] = val;
             }
             break;
diff --git a/ui/vnc.c b/ui/vnc.c
index dfc7459..2a2bb90 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -911,26 +911,30 @@ static int vnc_update_client(VncState *vs, int has_dirty)
         for (y = 0; y < height; y++) {
             int x;
             int last_x = -1;
-            for (x = 0; x < width / 16; x++) {
-                if (test_and_clear_bit(x, vs->dirty[y])) {
+            for (x = 0; x < width; x += 16) {
+                if (test_and_clear_bit(x/16, vs->dirty[y])) {
                     if (last_x == -1) {
                         last_x = x;
                     }
                 } else {
                     if (last_x != -1) {
-                        int h = find_and_clear_dirty_height(vs, y, last_x, x,
-                                                            height);
+                        int h = find_and_clear_dirty_height(vs, y, last_x/16,
+                                                            x/16, height);
 
-                        n += vnc_job_add_rect(job, last_x * 16, y,
-                                              (x - last_x) * 16, h);
+                        n += vnc_job_add_rect(job, last_x, y,
+                                              (x - last_x), h);
                     }
                     last_x = -1;
                 }
             }
             if (last_x != -1) {
-                int h = find_and_clear_dirty_height(vs, y, last_x, x, height);
-                n += vnc_job_add_rect(job, last_x * 16, y,
-                                      (x - last_x) * 16, h);
+                int h = find_and_clear_dirty_height(vs, y, last_x/16, x/16,
+                                                    height);
+                if (x > width) {
+                    x = width;
+                }
+                n += vnc_job_add_rect(job, last_x, y,
+                                      (x - last_x), h);
             }
         }
 
@@ -1861,7 +1865,7 @@ static void framebuffer_update_request(VncState *vs, int incremental,
                                        int w, int h)
 {
     int i;
-    const size_t width = surface_width(vs->vd->ds) / 16;
+    const size_t width = (surface_width(vs->vd->ds)+15) / 16;
     const size_t height = surface_height(vs->vd->ds);
 
     if (y_position > height) {
@@ -2686,10 +2690,6 @@ static int vnc_refresh_server_surface(VncDisplay *vd)
      * Check and copy modified bits from guest to server surface.
      * Update server dirty map.
      */
-    cmp_bytes = 64;
-    if (cmp_bytes > vnc_server_fb_stride(vd)) {
-        cmp_bytes = vnc_server_fb_stride(vd);
-    }
     if (vd->guest.format != VNC_SERVER_FB_FORMAT) {
         int width = pixman_image_get_width(vd->server);
         tmpbuf = qemu_pixman_linebuf_create(VNC_SERVER_FB_FORMAT, width);
@@ -2710,8 +2710,12 @@ static int vnc_refresh_server_surface(VncDisplay *vd)
             }
             server_ptr = server_row;
 
-            for (x = 0; x + 15 < width;
+            cmp_bytes = 64;
+            for (x = 0; x < width;
                     x += 16, guest_ptr += cmp_bytes, server_ptr += cmp_bytes) {
+                if (width - x < 16) {
+                    cmp_bytes = 4 * (width - x);
+                }
                 if (!test_and_clear_bit((x / 16), vd->guest.dirty[y]))
                     continue;
                 if (memcmp(server_ptr, guest_ptr, cmp_bytes) == 0)
--
1.7.10.4

2013/5/10 Andreas Färber <address@hidden>

Am 15.03.2013 19:14, schrieb Frediano Ziglio:

> Modern notebook support 136x768 resolution. The resolution width is

1366?

> not multiple of 16 causing some problems.

"a multiple"? (me not a native English speaker)

>
> Qemu VGA emulation require width resolution to be multiple of 8.

"QEMU"

>
> VNC implementation require width resolution to be multiple of 16.

"requires" or "implementations"

>
> This patch remove these limits. Was tested with a Windows machine with
> standard vga and 1366x768 as resolution. I had to update vgabios as
> version in qemu (pc-bios/vgabios-stdvga.bin) is quite old. I also had
> to add some patches on top of VGABIOS 0.7a to add some new
> resolutions.
>
> I have some doubt about this patch
> - are other UI (sdl, cocoa, qxl) happy if resolution is not multiple of 16 ?

SDL and Gtk+ should be easily testable; if you CC Peter Maydell or me we
can try to test Cocoa. CC'ing QXL guys.

> - scanline is computed exactly without any alignment (so 1366 8 bit is
> 1366 bytes) while getting vesa information from a laptop it seems to
> use some kind of alignment (if became 0x580 which is 1408 bytes).
> Perhaps should I change either VGABIOS and Qemu to make this
> alignment?

Concerns and personal comments are better placed below ---. :)

>
> Signed-off-by: Frediano Ziglio <address@hidden>
>
> ---
>  hw/vga.c |    2 +-

File has moved to hw/display/.

>  ui/vnc.c |   27 +++++++++++++--------------
>  2 files changed, 14 insertions(+), 15 deletions(-)

I don't see VGABIOS being updated here despite being mentioned above? Is
that done in a different patch? Still needed?

> diff --git a/hw/vga.c b/hw/vga.c
> index 1caf23d..d229f06 100644
> --- a/hw/vga.c
> +++ b/hw/vga.c
> @@ -651,7 +651,7 @@ void vbe_ioport_write_data(void *opaque, uint32_t
> addr, uint32_t val)
>              }
>              break;
>          case VBE_DISPI_INDEX_XRES:
> -            if ((val <= VBE_DISPI_MAX_XRES) && ((val & 7) == 0)) {
> +            if ((val <= VBE_DISPI_MAX_XRES) && ((val & 1) == 0)) {
>                  s->vbe_regs[s->vbe_index] = val;
>              }
>              break;
> diff --git a/ui/vnc.c b/ui/vnc.c
> index ff4e2ae..328d14d 100644
> --- a/ui/vnc.c
> +++ b/ui/vnc.c
> @@ -907,26 +907,27 @@ static int vnc_update_client(VncState *vs, int has_dirty)
>          for (y = 0; y < height; y++) {
>              int x;
>              int last_x = -1;
> -            for (x = 0; x < width / 16; x++) {
> -                if (test_and_clear_bit(x, vs->dirty[y])) {
> +            for (x = 0; x < width; x += 16) {
> +                if (test_and_clear_bit(x/16, vs->dirty[y])) {

[snip]

Please check if scripts/checkpatch.pl complains about missing spaces
around operators.

Regards,
Andreas

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