Messages in this thread Patch in this message | | | From | Eric Anholt <> | Subject | [PATCH 1/2] drm/vc4: Reject HDMI modes with too high of clocks. | Date | Wed, 20 Sep 2017 15:59:34 -0700 |
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Peter Robinson reported issues on Fedora with 4k monitors not having their modes filtered down to 1920x1080 on Raspberry Pi. Hopefully this resolves that.
Cc: Peter Robinson <pbrobinson@redhat.com> Signed-off-by: Eric Anholt <eric@anholt.net> ---
Note: This is an untested patch, since I'm away from hardware currently.
drivers/gpu/drm/vc4/vc4_hdmi.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c index fa37a1c07cf6..65826a4f208e 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -694,7 +694,22 @@ static void vc4_hdmi_encoder_enable(struct drm_encoder *encoder) } } +static enum drm_mode_status +vc5_hdmi_encoder_mode_valid(struct drm_encoder *crtc, + const struct drm_display_mode *mode) +{ + /* HSM clock must be 108% of the pixel clock. Additionally, + * the AXI clock needs to be at least 25% of pixel clock, but + * HSM ends up being the limiting factor. + */ + if (mode->clock > HSM_CLOCK_FREQ / (1000 * 108 / 100)) + return MODE_CLOCK_HIGH; + + return MODE_OK; +} + static const struct drm_encoder_helper_funcs vc4_hdmi_encoder_helper_funcs = { + .mode_valid = vc5_hdmi_encoder_mode_valid, .disable = vc4_hdmi_encoder_disable, .enable = vc4_hdmi_encoder_enable, }; -- 2.14.1
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