From a2fc4bd61e7ec3bb1f7c8b3d47272be813f88aea Mon Sep 17 00:00:00 2001 From: Shashank Sharma Date: Tue, 10 Oct 2017 15:37:44 +0530 Subject: [PATCH] drm/i915: Add retries for LSPCON detection 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 Cc: Imre Deak Signed-off-by: Shashank Sharma Reviewed-by: Imre Deak Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/1507630064-17908-4-git-send-email-shashank.sharma@intel.com --- drivers/gpu/drm/i915/intel_lspcon.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c index 768825472754..dcbc786479f9 100644 --- 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(struct intel_lspcon *lspcon) 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_lspcon *lspcon) 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; }