diff options
Diffstat (limited to 'config/coreboot/default/patches/0018-mb-dell-e6400-Use-100-MHz-reference-clock-for-displa.patch')
| -rw-r--r-- | config/coreboot/default/patches/0018-mb-dell-e6400-Use-100-MHz-reference-clock-for-displa.patch | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/config/coreboot/default/patches/0018-mb-dell-e6400-Use-100-MHz-reference-clock-for-displa.patch b/config/coreboot/default/patches/0018-mb-dell-e6400-Use-100-MHz-reference-clock-for-displa.patch new file mode 100644 index 00000000..b537346e --- /dev/null +++ b/config/coreboot/default/patches/0018-mb-dell-e6400-Use-100-MHz-reference-clock-for-displa.patch @@ -0,0 +1,51 @@ +From c075c12d5549cc6cfaa4fbb6bb3abd5e17503b04 Mon Sep 17 00:00:00 2001 +From: Nicholas Chin <nic.c3.14@gmail.com> +Date: Mon, 20 May 2024 10:24:16 -0600 +Subject: [PATCH 18/40] 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 <nic.c3.14@gmail.com> +--- + src/mainboard/dell/gm45_latitude/Kconfig | 2 ++ + src/northbridge/intel/gm45/Kconfig | 4 ++++ + 2 files changed, 6 insertions(+) + +diff --git a/src/mainboard/dell/gm45_latitude/Kconfig b/src/mainboard/dell/gm45_latitude/Kconfig +index 98ad18849c..4b026be2ba 100644 +--- a/src/mainboard/dell/gm45_latitude/Kconfig ++++ b/src/mainboard/dell/gm45_latitude/Kconfig +@@ -21,6 +21,8 @@ config BOARD_DELL_E6400 + select BOARD_DELL_GM45_LATITUDE_COMMON + + if BOARD_DELL_GM45_LATITUDE_COMMON ++config INTEL_GMA_DPLL_REF_FREQ ++ default 100000000 + + config MAINBOARD_DIR + default "dell/gm45_latitude" +diff --git a/src/northbridge/intel/gm45/Kconfig b/src/northbridge/intel/gm45/Kconfig +index fef0d735b3..fc5df8b11a 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 + +-- +2.47.3 + |