diff options
| author |   Linus Walleij <linus.walleij@linaro.org> | 2018-03-07 22:58:19 +0100 |
|---|---|---|
| committer | Linus Walleij <linus.walleij@linaro.org> | 2018-03-07 23:14:24 +0100 |
| commit | df99dd9202216f54eaf672e07808e9198d868af6 (patch) | |
| tree | ee75d257bc640dec1ff405deca483e83b63216e2 /drivers/gpu/drm/pl111/pl111_drv.c | |
| parent | drm/bridge: sii902x: Retry status read after DDI I2C (diff) | |
| download | linux-dev-df99dd9202216f54eaf672e07808e9198d868af6.tar.xz linux-dev-df99dd9202216f54eaf672e07808e9198d868af6.zip | |
drm/pl111: Use max memory bandwidth for resolution
We were previously selecting 1024x768 and 32BPP as the default
set-up for the PL111 consumers.
This does not work on elder systems: the device tree bindings
support a property "max-memory-bandwidth" in bytes/second that
states that if you exceed this the memory bus will saturate.
The result is flickering and unstable images.
Parse the "max-memory-bandwidth" and respect it when
intializing the driver. On the RealView PB11MP, Versatile and
Integrator/CP we get a nice console as default with this code.
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180307215819.15814-1-linus.walleij@linaro.org
Diffstat (limited to 'drivers/gpu/drm/pl111/pl111_drv.c')
| -rw-r--r-- | drivers/gpu/drm/pl111/pl111_drv.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/gpu/drm/pl111/pl111_drv.c b/drivers/gpu/drm/pl111/pl111_drv.c index e92a406c9ea9..4621259d5387 100644 --- a/drivers/gpu/drm/pl111/pl111_drv.c +++ b/drivers/gpu/drm/pl111/pl111_drv.c @@ -257,6 +257,12 @@ static int pl111_amba_probe(struct amba_device *amba_dev, drm->dev_private = priv; priv->variant = variant; + if (of_property_read_u32(dev->of_node, "max-memory-bandwidth", + &priv->memory_bw)) { + dev_info(dev, "no max memory bandwidth specified, assume unlimited\n"); + priv->memory_bw = 0; + } + /* The two variants swap this register */ if (variant->is_pl110) { priv->ienb = CLCD_PL110_IENB; |