Am 26.03.20 um 13:20 schrieb Nicolas Saenz Julienne:
Current mode validation impedes setting up some video modes which should be supported otherwise. Namely 1920x1200@60Hz.
Fix this by lowering the minimum HDMI state machine clock to pixel clock ratio allowed.
Fixes: 32e823c63e90 ("drm/vc4: Reject HDMI modes with too high of clocks") Reported-by: Stefan Wahren stefan.wahren@i2se.com Suggested-by: Dave Stevenson dave.stevenson@raspberrypi.com Signed-off-by: Nicolas Saenz Julienne nsaenzjulienne@suse.de
drivers/gpu/drm/vc4/vc4_hdmi.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c index cea18dc15f77..340719238753 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -681,11 +681,23 @@ static enum drm_mode_status vc4_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.
- /*
* As stated in RPi's vc4 firmware "HDMI state machine (HSM) clock must* be faster than pixel clock, infinitesimally faster, tested in* simulation. Otherwise, exact value is unimportant for HDMI* operation." This conflicts with bcm2835's vc4 documentation, which* states HSM's clock has to be at least 108% of the pixel clock.** Real life tests reveal that vc4's firmware statement holds up, and* users are able to use pixel clocks closer to HSM's, namely for* 1920x1200@60Hz. So it was decided to have leave a 1% margin between* both clocks. Which, for RPi0-3 implies a maximum pixel clock of
s/RPi0-3/bcm2835/ ?
Beside this nit:
Tested-by: Stefan Wahren stefan.wahre@i2se.com
Thanks