Re: [PATCH v2 8/8] drm: zynqmp_dp: Add debugfs interface for compliance testing

From: Tomi Valkeinen
Date: Thu Mar 21 2024 - 12:31:31 EST


On 21/03/2024 18:08, Sean Anderson wrote:
On 3/20/24 03:49, Tomi Valkeinen wrote:
On 20/03/2024 00:51, Sean Anderson wrote:

+/**
+ * enum test_pattern - Test patterns for test testing

"for test testing"? =)

@@ -1655,6 +2321,9 @@ static void zynqmp_dp_hpd_irq_work_func(struct work_struct *work)
u8 status[DP_LINK_STATUS_SIZE + 2];
int err;
+ if (READ_ONCE(dp->ignore_hpd))
+ return;
+
mutex_lock(&dp->lock);
err = drm_dp_dpcd_read(&dp->aux, DP_SINK_COUNT, status,
DP_LINK_STATUS_SIZE + 2);

Why do you need READ/WRITE_ONCE() for ignore_hpd?

It's not protected by dp->lock so we don't have to take it for
zynqmp_dp_hpd_work_func. Although maybe we should make a version of
zynqmp_dp_bridge_detect which assumes we already hold the lock.

Does using the macros solve some potential issue, or is it just for documenting that this variable is accessed without lock?

Tomi