[PATCH v3 05/13] efi: Use a fixed value for the timer clock
Simon Glass
sjg at chromium.org
Fri Mar 10 21:47:15 CET 2023
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 at chromium.org>
---
Changes in v3:
- Add a comment about the value
drivers/timer/tsc_timer.c | 9 +++++++++
1 file changed, 9 insertions(+)
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;
--
2.40.0.rc1.284.g88254d51c5-goog
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