diff mbox series

[v3,05/13] efi: Use a fixed value for the timer clock

Message ID 20230225222303.2232331-6-sjg@chromium.org
State Superseded, archived
Delegated to: Heinrich Schuchardt
Headers show
Series video: efi: Improve the EFI-app video console | expand

Commit Message

Simon Glass Feb. 25, 2023, 10:22 p.m. UTC 
It is not yet clear how to read the timer via EFI. The current value seems
much too high on a Framework laptop I tried. Adjust it to a lower
hard-coded value for now.

Signed-off-by: Simon Glass <sjg@chromium.org>
---

Changes in v3:
- Add a comment about the value

 drivers/timer/tsc_timer.c | 9 +++++++++
 1 file changed, 9 insertions(+)
diff mbox series

Patch

diff --git a/drivers/timer/tsc_timer.c b/drivers/timer/tsc_timer.c
index 192c7b71a5a..f86a0b86921 100644
--- a/drivers/timer/tsc_timer.c
+++ b/drivers/timer/tsc_timer.c
@@ -404,6 +404,15 @@  static void tsc_timer_ensure_setup(bool early)
 	if (!gd->arch.clock_rate) {
 		unsigned long fast_calibrate;
 
+		/**
+		 * There is no obvious way to obtain this information from EFI
+		 * boot services. This value was measured on a Framework Laptop
+		 * which has a 12th Gen Intel Core
+		 */
+		if (IS_ENABLED(CONFIG_EFI_APP)) {
+			fast_calibrate = 2750;
+			goto done;
+		}
 		fast_calibrate = native_calibrate_tsc();
 		if (fast_calibrate)
 			goto done;