Patrick Georgi submitted this change.
mb/siemens/mc_apl5: Disable IGD if no EDID data available
To avoid possible panel failures due to incorrect timing settings for
PTN3460, the internal graphic device should be disabled.
Change-Id: Ie0b9ed99fb78461bb48d6f2ff328643cd8c2cd15
Signed-off-by: Mario Scheithauer <mario.scheithauer@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35242
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Werner Zeh <werner.zeh@siemens.com>
---
M src/mainboard/siemens/mc_apl1/variants/mc_apl5/ptn3460.c
1 file changed, 25 insertions(+), 0 deletions(-)
diff --git a/src/mainboard/siemens/mc_apl1/variants/mc_apl5/ptn3460.c b/src/mainboard/siemens/mc_apl1/variants/mc_apl5/ptn3460.c
index f6fed97..2cc7dd4 100644
--- a/src/mainboard/siemens/mc_apl1/variants/mc_apl5/ptn3460.c
+++ b/src/mainboard/siemens/mc_apl1/variants/mc_apl5/ptn3460.c
@@ -16,9 +16,32 @@
#include <console/console.h>
#include <hwilib.h>
#include <device/i2c_simple.h>
+#include <device/pci_ops.h>
+#include <soc/pci_devs.h>
#include <types.h>
#include <variant/ptn3460.h>
+static void igd_disable(void)
+{
+ struct device *root_dev = pcidev_path_on_root(SA_DEVFN_ROOT);
+ uint8_t deven;
+ uint16_t ggc;
+
+ /* GMCH Graphics Control Register */
+ ggc = pci_read_config16(root_dev, 0x50);
+ /* Set size of Graphics Translation Table Memory (GGMS) [7:6]
+ * to 0 and select 0 MB for Graphics Memory (GMS) [15:8]. */
+ ggc &= ~(0xffc0);
+ /* Disable IGD VGA (IVD). */
+ ggc |= 0x2;
+ pci_write_config16(root_dev, 0x50, ggc);
+ /* Device Enable Register */
+ deven = pci_read_config8(root_dev, 0x54);
+ /* Disable IGD device (D2F0EN). */
+ deven &= ~(0x10);
+ pci_write_config8(root_dev, 0x54, deven);
+}
+
/**
* This function sets up the DP2LVDS-converter to be used with the appropriate
* lcd panel.
@@ -42,6 +65,8 @@
/* Get all needed information from hwinfo block. */
if (hwilib_get_field(Edid, edid_data, sizeof(edid_data)) !=
sizeof(edid_data)) {
+ /* Disable IGD to avoid panel failures. */
+ igd_disable();
printk(BIOS_ERR, "LCD: No EDID data available in %s\n",
hwi_block);
return 1;
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