From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Jani Nikula <jani.nikula@intel.com>,
Nicolas Suzor <nic@suzor.com>, Todd Previte <tprevite@gmail.com>,
Daniel Vetter <daniel.vetter@ffwll.ch>
Subject: [ 10/16] drm/i915/dp: increase i2c-over-aux retry interval on AUX DEFER
Date: Wed, 2 Oct 2013 21:05:34 -0700 [thread overview]
Message-ID: <20131003040446.243245338@linuxfoundation.org> (raw)
In-Reply-To: <20131003040445.523176877@linuxfoundation.org>
3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jani Nikula <jani.nikula@intel.com>
commit 8d16f258217f2f583af1fd57c5144aa4bbe73e48 upstream.
There is no clear cut rules or specs for the retry interval, as there
are many factors that affect overall response time. Increase the
interval, and even more so on branch devices which may have limited i2c
bit rates.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reference: https://bugs.freedesktop.org/show_bug.cgi?id=60263
Tested-by: Nicolas Suzor <nic@suzor.com>
Reviewed-by: Todd Previte <tprevite@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/i915/intel_dp.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -625,7 +625,18 @@ intel_dp_i2c_aux_ch(struct i2c_adapter *
DRM_DEBUG_KMS("aux_ch native nack\n");
return -EREMOTEIO;
case AUX_NATIVE_REPLY_DEFER:
- udelay(100);
+ /*
+ * For now, just give more slack to branch devices. We
+ * could check the DPCD for I2C bit rate capabilities,
+ * and if available, adjust the interval. We could also
+ * be more careful with DP-to-Legacy adapters where a
+ * long legacy cable may force very low I2C bit rates.
+ */
+ if (intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] &
+ DP_DWN_STRM_PORT_PRESENT)
+ usleep_range(500, 600);
+ else
+ usleep_range(300, 400);
continue;
default:
DRM_ERROR("aux_ch invalid native reply 0x%02x\n",
next prev parent reply other threads:[~2013-10-03 4:05 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-03 4:05 [ 00/16] 3.4.65-stable review Greg Kroah-Hartman
2013-10-03 4:05 ` [ 01/16] x86/reboot: Add quirk to make Dell C6100 use reboot=pci automatically Greg Kroah-Hartman
2013-10-03 4:05 ` [ 02/16] x86, efi: Dont map Boot Services on i386 Greg Kroah-Hartman
2013-10-03 4:05 ` [ 03/16] staging: vt6656: [BUG] main_usb.c oops on device_close move flag earlier Greg Kroah-Hartman
2013-10-03 4:05 ` [ 04/16] xhci: Ensure a command structure points to the correct trb on the command ring Greg Kroah-Hartman
2013-10-03 4:05 ` [ 05/16] xhci: Fix oops happening after address device timeout Greg Kroah-Hartman
2013-10-03 4:05 ` [ 06/16] xhci: Fix race between ep halt and URB cancellation Greg Kroah-Hartman
2013-10-03 4:05 ` [ 07/16] usb/core/devio.c: Dont reject control message to endpoint with wrong direction bit Greg Kroah-Hartman
2013-10-03 4:05 ` [ 08/16] dm snapshot: workaround for a false positive lockdep warning Greg Kroah-Hartman
2013-10-03 4:05 ` [ 09/16] dm-snapshot: fix performance degradation due to small hash size Greg Kroah-Hartman
2013-10-03 4:05 ` Greg Kroah-Hartman [this message]
2013-10-03 4:05 ` [ 11/16] drm/radeon: disable tests/benchmarks if accel is disabled Greg Kroah-Hartman
2013-10-03 4:05 ` [ 12/16] hwmon: (applesmc) Check key count before proceeding Greg Kroah-Hartman
2013-10-03 4:05 ` [ 13/16] ALSA: compress: Fix compress device unregister Greg Kroah-Hartman
2013-10-03 4:05 ` [ 14/16] mm, memcg: give exiting processes access to memory reserves Greg Kroah-Hartman
2013-10-03 4:05 ` [ 15/16] mm: fix aio performance regression for database caused by THP Greg Kroah-Hartman
2013-10-03 4:05 ` [ 16/16] HID: LG: validate HID output report details Greg Kroah-Hartman
2013-10-03 13:30 ` [ 00/16] 3.4.65-stable review Guenter Roeck
2013-10-03 18:40 ` Greg Kroah-Hartman
2013-10-03 21:19 ` Guenter Roeck
2013-10-03 18:39 ` Greg Kroah-Hartman
2013-10-04 0:24 ` Shuah Khan
2013-10-04 2:38 ` Greg Kroah-Hartman
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