gma500: Discard modes that don't fit in stolen memory

[This fixes a crash on boot if the system is plugged into an HDTV so it's
 probably appropriate to push even though it didn't make the window. We could
 be cleverer about this but the simple version seems to be the safe one]

From: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>

At the moment we cannot allocate more than stolen memory size for framebuffers.
To get around that issues we discard modes that doesn't fit. This is a temporary
solution until we can freely allocate framebuffer memory.

[Currently the framebuffer needs to be linear in kernel space due to limits
 in the kernel fb layer - AC]

Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 6 insertions, 8 deletions

diff --git a/drivers/gpu/drm/gma500/cdv_intel_hdmi.c b/drivers/gpu/drm/gma500/cdv_intel_hdmi.c
index 50d7cfb51662..de25560e629d 100644
--- a/drivers/gpu/drm/gma500/cdv_intel_hdmi.c
+++ b/drivers/gpu/drm/gma500/cdv_intel_hdmi.c
@@ -241,6 +241,7 @@ static int cdv_hdmi_get_modes(struct drm_connector *connector)
 static int cdv_hdmi_mode_valid(struct drm_connector *connector,
                                  struct drm_display_mode *mode)
 {
+        struct drm_psb_private *dev_priv = connector->dev->dev_private;
 
         if (mode->clock > 165000)
                 return MODE_CLOCK_HIGH;
@@ -255,14 +256,11 @@ static int cdv_hdmi_mode_valid(struct drm_connector *connector,
         if (mode->flags & DRM_MODE_FLAG_INTERLACE)
                 return MODE_NO_INTERLACE;
 
-        /*
-         * FIXME: for now we limit the size to 1680x1050 on CDV, otherwise it
-         * will go beyond the stolen memory size allocated to the framebuffer
-         */
-        if (mode->hdisplay > 1680)
-                return MODE_PANEL;
-        if (mode->vdisplay > 1050)
-                return MODE_PANEL;
+        /* We assume worst case scenario of 32 bpp here, since we don't know */
+        if ((ALIGN(mode->hdisplay * 4, 64) * mode->vdisplay) >
+            dev_priv->vram_stolen_size)
+                return MODE_MEM;
+
         return MODE_OK;
 }