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-rw-r--r--meta-amd-bsp/recipes-kernel/linux-4.19/linux-yocto-4.19.8/1196-drm-amd-display-Use-udelay-when-waiting-between-aux-.patch39
1 files changed, 39 insertions, 0 deletions
diff --git a/meta-amd-bsp/recipes-kernel/linux-4.19/linux-yocto-4.19.8/1196-drm-amd-display-Use-udelay-when-waiting-between-aux-.patch b/meta-amd-bsp/recipes-kernel/linux-4.19/linux-yocto-4.19.8/1196-drm-amd-display-Use-udelay-when-waiting-between-aux-.patch
new file mode 100644
index 00000000..251f7a74
--- /dev/null
+++ b/meta-amd-bsp/recipes-kernel/linux-4.19/linux-yocto-4.19.8/1196-drm-amd-display-Use-udelay-when-waiting-between-aux-.patch
@@ -0,0 +1,39 @@
+From 74c19b3e67b5160f55bccf69148e231183a2bf07 Mon Sep 17 00:00:00 2001
+From: John Barberiz <John.Barberiz@amd.com>
+Date: Wed, 16 Jan 2019 17:21:31 -0500
+Subject: [PATCH 1196/2940] drm/amd/display: Use udelay when waiting between
+ aux retries
+
+[Why]
+"IRQ_HPD Pulse Length Test" DP compliance test
+fails. Test complains that certain DPCD registers
+are not read within 100 ms.
+
+[How]
+msleep is inaccurate for small values. Used udelay
+instead for accuracy.
+
+Change-Id: I4990fc56c7632fba373f2dbf64ac803d64619529
+Signed-off-by: John Barberiz <John.Barberiz@amd.com>
+Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
+Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
+---
+ drivers/gpu/drm/amd/display/dc/dce/dce_aux.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
+index adbb22224e1a..4febf4ef7240 100644
+--- a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
++++ b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
+@@ -516,7 +516,7 @@ bool dce_aux_transfer_with_retries(struct ddc_service *ddc,
+ }
+ }
+
+- msleep(1);
++ udelay(1000);
+ }
+ return false;
+ }
+--
+2.17.1
+