From b42ca30081b25cbabfb2659adca9d935ef3a8399 Mon Sep 17 00:00:00 2001 From: Nicholas Chin Date: Mon, 20 May 2024 10:24:16 -0600 Subject: [PATCH 3/3] mb/dell/e6400: Use 100 MHz reference clock for display The E6400 uses a 100 MHz reference clock for spread spectrum support on LVDS, whereas libgfxinit previously assumed a 96 MHz input clock. For the more common 1280 x 800 display panels, the numerical error was not large enough to cause noticable issues, but the actual pixel clock frequency derived from a 100 MHz reference using PLL configs calculated assuming a 96 MHz reference was not close enough for 1440 x 900 panels, which require a much higher pixel clock. This resulted in a garbled display in the pre-OS graphics environment provided by libgfxinit. Signed-off-by: Nicholas Chin --- src/mainboard/dell/e6400/Kconfig | 3 +++ src/northbridge/intel/gm45/Kconfig | 4 ++++ 2 files changed, 7 insertions(+) diff --git a/src/mainboard/dell/e6400/Kconfig b/src/mainboard/dell/e6400/Kconfig index 417d95fd5d..6fe1b1c456 100644 --- a/src/mainboard/dell/e6400/Kconfig +++ b/src/mainboard/dell/e6400/Kconfig @@ -19,6 +19,9 @@ config BOARD_SPECIFIC_OPTIONS select INTEL_GMA_HAVE_VBT select EC_DELL_MEC5035 +config INTEL_GMA_DPLL_REF_FREQ + default 100000000 + config MAINBOARD_DIR default "dell/e6400" diff --git a/src/northbridge/intel/gm45/Kconfig b/src/northbridge/intel/gm45/Kconfig index 8059e7ee80..5df5a93296 100644 --- a/src/northbridge/intel/gm45/Kconfig +++ b/src/northbridge/intel/gm45/Kconfig @@ -14,6 +14,10 @@ config NORTHBRIDGE_INTEL_GM45 if NORTHBRIDGE_INTEL_GM45 +config INTEL_GMA_DPLL_REF_FREQ + int + default 96000000 + config VBOOT select VBOOT_STARTS_IN_BOOTBLOCK -- 2.39.2