[Mesa-dev] [PATCH mesa v2 2/2] nv30: Disable msaa unless requested from the env by NV30_MAX_MSAA

[Hans de Goede]

Some modern apps try to use msaa without keeping in mind the
restrictions on videomem of older cards. Resulting in dmesg saying:

 [ 1197.850642] nouveau E[soffice.bin[3785]] fail ttm_validate
 [ 1197.850648] nouveau E[soffice.bin[3785]] validating bo list
 [ 1197.850654] nouveau E[soffice.bin[3785]] validate: -12

Because we are running out of video memory, after which the program
using the msaa visual freezes, and eventually the entire system freezes.

To work around this we do not allow msaa visauls by default and allow
the user to override this via NV30_MAX_MSAA.

Signed-off-by: Hans de Goede <hdegoede at redhat.com>
---
Changes in v2:
-Allow re-enabling msaa by setting NV30_MAX_MSAA in the environment
---
 src/gallium/drivers/nouveau/nv30/nv30_screen.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/gallium/drivers/nouveau/nv30/nv30_screen.c b/src/gallium/drivers/nouveau/nv30/nv30_screen.c
index 7aad26b..4b77f43 100644
--- a/src/gallium/drivers/nouveau/nv30/nv30_screen.c
+++ b/src/gallium/drivers/nouveau/nv30/nv30_screen.c
@@ -319,8 +319,28 @@ nv30_screen_is_format_supported(struct pipe_screen *pscreen,
                                 unsigned sample_count,
                                 unsigned bindings)
 {
-   if (sample_count > 4)
+   unsigned int max_sample_count;
+
+   /*
+    * Some modern apps try to use msaa without keeping in mind the
+    * restrictions on videomem of older cards. Resulting in dmesg saying:
+    * [ 1197.850642] nouveau E[soffice.bin[3785]] fail ttm_validate
+    * [ 1197.850648] nouveau E[soffice.bin[3785]] validating bo list
+    * [ 1197.850654] nouveau E[soffice.bin[3785]] validate: -12
+    *
+    * Because we are running out of video memory, after which the program
+    * using the msaa visual freezes, and eventually the entire system freezes.
+    *
+    * To work around this we do not allow msaa visauls by default and allow
+    * the user to override this via NV30_MAX_MSAA.
+    */
+   max_sample_count = debug_get_num_option("NV30_MAX_MSAA", 0);
+   if (max_sample_count > 4)
+      max_sample_count = 4;
+
+   if (sample_count > max_sample_count)
       return false;
+
    if (!(0x00000017 & (1 << sample_count)))
       return false;
 
-- 
2.4.3