[Qemu-devel] [PATCH] bcm2835_property: use cached values when querying framebuffer

[Sylvain Garrigues <sylvain@sylvaingarrigues.com>]

As the framebuffer settings are copied into the result message before it is
reconfigured, inconsistent behavior can happen when, for instance, you set with
a single message the width, height, and depth, and ask at the same time to
allocate the buffer and get the pitch and the size.

In this case, the reported pitch and size would be incorrect as they were
computed with the initial values of width, height and depth, not the ones the
client requested.

Signed-off-by: Sylvain Garrigues <sylvain@sylvaingarrigues.com>
Reviewed-by: Andrew Baumann <Andrew.Baumann@microsoft.com>
---
 hw/misc/bcm2835_property.c | 31 ++++++++++++++++++++++---------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/hw/misc/bcm2835_property.c b/hw/misc/bcm2835_property.c
index 530411f..96e3b8f 100644
--- a/hw/misc/bcm2835_property.c
+++ b/hw/misc/bcm2835_property.c
@@ -21,6 +21,7 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value)
     int n;
     uint32_t offset, length, color;
     uint32_t xres, yres, xoffset, yoffset, bpp, pixo, alpha;
+    uint32_t tmp_xres, tmp_yres, tmp_xoffset, tmp_yoffset, tmp_bpp, tmp_pixo, tmp_alpha;
     uint32_t *newxres = NULL, *newyres = NULL, *newxoffset = NULL,
         *newyoffset = NULL, *newbpp = NULL, *newpixo = NULL, *newalpha = NULL;
 
@@ -139,7 +140,10 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value)
 
         case 0x00040001: /* Allocate buffer */
             stl_le_phys(&s->dma_as, value + 12, s->fbdev->base);
-            stl_le_phys(&s->dma_as, value + 16, s->fbdev->size);
+            tmp_xres = newxres != NULL ? *newxres : s->fbdev->xres;
+            tmp_yres = newyres != NULL ? *newyres : s->fbdev->yres;
+            tmp_bpp = newbpp != NULL ? *newbpp : s->fbdev->bpp;
+            stl_le_phys(&s->dma_as, value + 16, tmp_xres * tmp_yres * tmp_bpp / 8);
             resplen = 8;
             break;
         case 0x00048001: /* Release buffer */
@@ -150,8 +154,10 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value)
             break;
         case 0x00040003: /* Get display width/height */
         case 0x00040004:
-            stl_le_phys(&s->dma_as, value + 12, s->fbdev->xres);
-            stl_le_phys(&s->dma_as, value + 16, s->fbdev->yres);
+            tmp_xres = newxres != NULL ? *newxres : s->fbdev->xres;
+            tmp_yres = newyres != NULL ? *newyres : s->fbdev->yres;
+            stl_le_phys(&s->dma_as, value + 12, tmp_xres);
+            stl_le_phys(&s->dma_as, value + 16, tmp_yres);
             resplen = 8;
             break;
         case 0x00044003: /* Test display width/height */
@@ -167,7 +173,8 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value)
             resplen = 8;
             break;
         case 0x00040005: /* Get depth */
-            stl_le_phys(&s->dma_as, value + 12, s->fbdev->bpp);
+            tmp_bpp = newbpp != NULL ? *newbpp : s->fbdev->bpp;
+            stl_le_phys(&s->dma_as, value + 12, tmp_bpp);
             resplen = 4;
             break;
         case 0x00044005: /* Test depth */
@@ -179,7 +186,8 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value)
             resplen = 4;
             break;
         case 0x00040006: /* Get pixel order */
-            stl_le_phys(&s->dma_as, value + 12, s->fbdev->pixo);
+            tmp_pixo = newpixo != NULL ? *newpixo : s->fbdev->pixo;
+            stl_le_phys(&s->dma_as, value + 12, tmp_pixo);
             resplen = 4;
             break;
         case 0x00044006: /* Test pixel order */
@@ -191,7 +199,8 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value)
             resplen = 4;
             break;
         case 0x00040007: /* Get alpha */
-            stl_le_phys(&s->dma_as, value + 12, s->fbdev->alpha);
+            tmp_alpha = newalpha != NULL ? *newalpha : s->fbdev->alpha;
+            stl_le_phys(&s->dma_as, value + 12, tmp_alpha);
             resplen = 4;
             break;
         case 0x00044007: /* Test pixel alpha */
@@ -203,12 +212,16 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value)
             resplen = 4;
             break;
         case 0x00040008: /* Get pitch */
-            stl_le_phys(&s->dma_as, value + 12, s->fbdev->pitch);
+            tmp_xres = newxres != NULL ? *newxres : s->fbdev->xres;
+            tmp_bpp = newbpp != NULL ? *newbpp : s->fbdev->bpp;
+            stl_le_phys(&s->dma_as, value + 12, tmp_xres * tmp_bpp / 8);
             resplen = 4;
             break;
         case 0x00040009: /* Get virtual offset */
-            stl_le_phys(&s->dma_as, value + 12, s->fbdev->xoffset);
-            stl_le_phys(&s->dma_as, value + 16, s->fbdev->yoffset);
+            tmp_xoffset = newxoffset != NULL ? *newxoffset : s->fbdev->xoffset;
+            tmp_yoffset = newyoffset != NULL ? *newyoffset : s->fbdev->yoffset;
+            stl_le_phys(&s->dma_as, value + 12, tmp_xoffset);
+            stl_le_phys(&s->dma_as, value + 16, tmp_yoffset);
             resplen = 8;
             break;
         case 0x00044009: /* Test virtual offset */
-- 
2.8.1