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drivers/intel/gma: Fix alignment of extended VBT in opregion

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Intel's reference implementation in Slimbootloader pads the area
allocated for the extended VBT to the nearest 512-byte boundary, which
strongly suggests that the Windows driver expects the same.

TEST=build/boot Linux 6.9, Win11 on starlabs/starlite_adl, verify
VBT read properly by OS.

Change-Id: Ib3784eea6eb929ffec9672fc123b833c11c057e8
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/86275
Reviewed-by: Jérémy Compostella <jeremy.compostella@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
This commit is contained in:
Matt DeVillier 2025-01-31 11:28:20 -06:00 • committed by Sean Rhodes
commit f56b8b49e8
1 changed files with 7 additions and 4 deletions
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11
src/drivers/intel/gma/opregion.c
View file

@ -287,7 +287,7 @@ static inline bool uses_relative_vbt_addr(opregion_header_t *header)
* values correctly for the opregion.
*/
static void opregion_add_ext_vbt(igd_opregion_t *opregion, uint8_t *ext_vbt,
optionrom_vbt_t *vbt)
optionrom_vbt_t *vbt, size_t ext_vbt_size)
{
opregion_header_t *header = &opregion->header;
/* Copy VBT into extended VBT region (at offset 8 KiB) */
@ -301,7 +301,7 @@ static void opregion_add_ext_vbt(igd_opregion_t *opregion, uint8_t *ext_vbt,
else
opregion->mailbox3.rvda = (uintptr_t)ext_vbt;
opregion->mailbox3.rvds = vbt->hdr_vbt_size;
opregion->mailbox3.rvds = ext_vbt_size;
}
/* Initialize IGD OpRegion, called from ACPI code and OS drivers */
@ -311,6 +311,7 @@ enum cb_err intel_gma_init_igd_opregion(void)
struct region_device rdev;
optionrom_vbt_t *vbt = NULL;
size_t opregion_size = sizeof(igd_opregion_t);
size_t ext_vbt_size;
if (acpi_is_wakeup_s3())
return intel_gma_restore_opregion();
@ -331,7 +332,9 @@ enum cb_err intel_gma_init_igd_opregion(void)
}
/* Add the space for the extended VBT header even if it's not used */
opregion_size += vbt->hdr_vbt_size;
/* Align the VBT to nearest 512 byte boundary */
ext_vbt_size = ALIGN_UP(vbt->hdr_vbt_size, 512);
opregion_size += ext_vbt_size;
opregion = cbmem_add(CBMEM_ID_IGD_OPREGION, opregion_size);
if (!opregion) {
@ -353,7 +356,7 @@ enum cb_err intel_gma_init_igd_opregion(void)
if (is_ext_vbt_required(opregion, vbt)) {
/* Place extended VBT just after opregion */
uint8_t *ext_vbt = (uint8_t *)opregion + sizeof(*opregion);
opregion_add_ext_vbt(opregion, ext_vbt, vbt);
opregion_add_ext_vbt(opregion, ext_vbt, vbt, ext_vbt_size);
} else {
/* Raw VBT size which can fit in gvd1 */
memcpy(opregion->vbt.gvd1, vbt, vbt->hdr_vbt_size);