From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751845AbdITW7k (ORCPT ); Wed, 20 Sep 2017 18:59:40 -0400 Received: from anholt.net ([50.246.234.109]:35132 "EHLO anholt.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751547AbdITW7i (ORCPT ); Wed, 20 Sep 2017 18:59:38 -0400 From: Eric Anholt To: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org, Eric Anholt , Peter Robinson Subject: [PATCH 1/2] drm/vc4: Reject HDMI modes with too high of clocks. Date: Wed, 20 Sep 2017 15:59:34 -0700 Message-Id: <20170920225935.14566-1-eric@anholt.net> X-Mailer: git-send-email 2.14.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Signed-off-by: Eric Anholt --- 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