diff mbox series

[v2,6/6] drm/gud: Enable synchronous flushing by default

Message ID 20221122-gud-shadow-plane-v2-6-435037990a83@tronnes.org (mailing list archive)
State New, archived
Headers show
Series drm/gud: Use the shadow plane helper | expand

Commit Message

Noralf Trønnes via B4 Relay Nov. 30, 2022, 7:26 p.m. UTC
From: Noralf Trønnes <noralf@tronnes.org>

gud has a module parameter that controls whether framebuffer flushing
happens synchronously during the commit or asynchronously in a worker.

GNOME before version 3.38 handled all displays in the same rendering loop.
This lead to gud slowing down the refresh rate for a faster monitor. This
has now been fixed so lets change the default.

The plan is to remove async flushing in the future. The code is now
structured in a way that makes it easy to do this.

Link: https://blogs.gnome.org/shell-dev/2020/07/02/splitting-up-the-frame-clock/
Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
---
 drivers/gpu/drm/gud/gud_pipe.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

Comments

Thomas Zimmermann Dec. 1, 2022, 8:57 a.m. UTC | #1
Am 30.11.22 um 20:26 schrieb Noralf Trønnes via B4 Submission Endpoint:
> From: Noralf Trønnes <noralf@tronnes.org>
> 
> gud has a module parameter that controls whether framebuffer flushing
> happens synchronously during the commit or asynchronously in a worker.
> 
> GNOME before version 3.38 handled all displays in the same rendering loop.
> This lead to gud slowing down the refresh rate for a faster monitor. This
> has now been fixed so lets change the default.
> 
> The plan is to remove async flushing in the future. The code is now
> structured in a way that makes it easy to do this.
> 
> Link: https://blogs.gnome.org/shell-dev/2020/07/02/splitting-up-the-frame-clock/
> Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
> Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>

> ---
>   drivers/gpu/drm/gud/gud_pipe.c | 12 ++++--------
>   1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/gud_pipe.c
> index 92189474a7ed..62c43d3632d4 100644
> --- a/drivers/gpu/drm/gud/gud_pipe.c
> +++ b/drivers/gpu/drm/gud/gud_pipe.c
> @@ -25,17 +25,13 @@
>   #include "gud_internal.h"
>   
>   /*
> - * Some userspace rendering loops runs all displays in the same loop.
> + * Some userspace rendering loops run all displays in the same loop.
>    * This means that a fast display will have to wait for a slow one.
> - * For this reason gud does flushing asynchronous by default.
> - * The down side is that in e.g. a single display setup userspace thinks
> - * the display is insanely fast since the driver reports back immediately
> - * that the flush/pageflip is done. This wastes CPU and power.
> - * Such users might want to set this module parameter to false.
> + * Such users might want to enable this module parameter.
>    */
> -static bool gud_async_flush = true;
> +static bool gud_async_flush;
>   module_param_named(async_flush, gud_async_flush, bool, 0644);
> -MODULE_PARM_DESC(async_flush, "Enable asynchronous flushing [default=true]");
> +MODULE_PARM_DESC(async_flush, "Enable asynchronous flushing [default=0]");
>   
>   /*
>    * FIXME: The driver is probably broken on Big Endian machines.
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/gud_pipe.c
index 92189474a7ed..62c43d3632d4 100644
--- a/drivers/gpu/drm/gud/gud_pipe.c
+++ b/drivers/gpu/drm/gud/gud_pipe.c
@@ -25,17 +25,13 @@ 
 #include "gud_internal.h"
 
 /*
- * Some userspace rendering loops runs all displays in the same loop.
+ * Some userspace rendering loops run all displays in the same loop.
  * This means that a fast display will have to wait for a slow one.
- * For this reason gud does flushing asynchronous by default.
- * The down side is that in e.g. a single display setup userspace thinks
- * the display is insanely fast since the driver reports back immediately
- * that the flush/pageflip is done. This wastes CPU and power.
- * Such users might want to set this module parameter to false.
+ * Such users might want to enable this module parameter.
  */
-static bool gud_async_flush = true;
+static bool gud_async_flush;
 module_param_named(async_flush, gud_async_flush, bool, 0644);
-MODULE_PARM_DESC(async_flush, "Enable asynchronous flushing [default=true]");
+MODULE_PARM_DESC(async_flush, "Enable asynchronous flushing [default=0]");
 
 /*
  * FIXME: The driver is probably broken on Big Endian machines.