From a2fc4bd61e7ec3bb1f7c8b3d47272be813f88aea Mon Sep 17 00:00:00 2001
From: Shashank Sharma <shashank.sharma@intel.com>
Date: Tue, 10 Oct 2017 15:37:44 +0530
Subject: [PATCH] drm/i915: Add retries for LSPCON detection
Git-commit: a2fc4bd61e7ec3bb1f7c8b3d47272be813f88aea
Patch-mainline: v4.15-rc1
References: FATE#322643 bsc#1055900
We read the dp dual mode Adapter identifier to detect the
LSPCON device. It's been observed from the CI testing that in
few cases, this read can get delayed or fail. For such scenarios,
LSPCON vendors suggest to retry the read operation.
This patch adds retry in the probe function, while reading
LSPCON identifier.
V3: added this patch in the series
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102294
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102295
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102359
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103186
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1507630064-17908-4-git-send-email-shashank.sharma@intel.com
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpu/drm/i915/intel_lspcon.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/i915/intel_lspcon.c
+++ b/drivers/gpu/drm/i915/intel_lspcon.c
@@ -132,6 +132,7 @@ static bool lspcon_wake_native_aux_ch(st
static bool lspcon_probe(struct intel_lspcon *lspcon)
{
+ int retry;
enum drm_dp_dual_mode_type adaptor_type;
struct i2c_adapter *adapter = &lspcon_to_intel_dp(lspcon)->aux.ddc;
enum drm_lspcon_mode expected_mode;
@@ -140,10 +141,18 @@ static bool lspcon_probe(struct intel_ls
DRM_LSPCON_MODE_PCON : DRM_LSPCON_MODE_LS;
/* Lets probe the adaptor and check its type */
- adaptor_type = drm_dp_dual_mode_detect(adapter);
+ for (retry = 0; retry < 6; retry++) {
+ if (retry)
+ usleep_range(500, 1000);
+
+ adaptor_type = drm_dp_dual_mode_detect(adapter);
+ if (adaptor_type == DRM_DP_DUAL_MODE_LSPCON)
+ break;
+ }
+
if (adaptor_type != DRM_DP_DUAL_MODE_LSPCON) {
DRM_DEBUG_KMS("No LSPCON detected, found %s\n",
- drm_dp_get_dual_mode_type_name(adaptor_type));
+ drm_dp_get_dual_mode_type_name(adaptor_type));
return false;
}