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| author |   Noralf Trønnes <noralf@tronnes.org> | 2021-07-03 16:13:21 +0200 |
|---|---|---|
| committer | Noralf Trønnes <noralf@tronnes.org> | 2021-07-08 14:34:28 +0200 |
| commit | a0356899ebe8ecde0da9c5685cc47154db973a5e (patch) | |
| tree | 1e20ddd7dc8ae2d7d3cf0c2d0e061b3a217cf9b8 | |
| parent | drm/gud: Add Raspberry Pi Pico ID (diff) | |
| download | linux-dev-a0356899ebe8ecde0da9c5685cc47154db973a5e.tar.xz linux-dev-a0356899ebe8ecde0da9c5685cc47154db973a5e.zip | |
drm/gud: Add async_flush module parameter
Provide a way for userspace to choose synchronous flushing/pageflips.
This helps save CPU and power.
It is also useful for test scripts since userspace can know when a flush
has happended and wait before doing the next visual test.
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Peter Stuge <peter@stuge.se>
Link: https://patchwork.freedesktop.org/patch/msgid/20210703141321.35494-2-noralf@tronnes.org
| -rw-r--r-- | drivers/gpu/drm/gud/gud_pipe.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/gud_pipe.c index e0fb6cc969a3..8f56bf618ac2 100644 --- a/drivers/gpu/drm/gud/gud_pipe.c +++ b/drivers/gpu/drm/gud/gud_pipe.c @@ -24,6 +24,19 @@ #include "gud_internal.h" /* + * Some userspace rendering loops runs 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. + */ +static bool gud_async_flush = true; +module_param_named(async_flush, gud_async_flush, bool, 0644); +MODULE_PARM_DESC(async_flush, "Enable asynchronous flushing [default=true]"); + +/* * FIXME: The driver is probably broken on Big Endian machines. * See discussion: * https://lore.kernel.org/dri-devel/CAKb7UvihLX0hgBOP3VBG7O+atwZcUVCPVuBdfmDMpg0NjXe-cQ@mail.gmail.com/ @@ -578,6 +591,8 @@ void gud_pipe_update(struct drm_simple_display_pipe *pipe, if (gdrm->flags & GUD_DISPLAY_FLAG_FULL_UPDATE) drm_rect_init(&damage, 0, 0, fb->width, fb->height); gud_fb_queue_damage(gdrm, fb, &damage); + if (!gud_async_flush) + flush_work(&gdrm->work); } if (!crtc->state->enable) |