From: Daniel Vetter <daniel@ffwll.ch>
To: Todd Previte <tprevite@gmail.com>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 12/12] drm/i915: Add a delay in Displayport AUX transactions for compliance testing
Date: Tue, 15 Jul 2014 09:46:28 +0200 [thread overview]
Message-ID: <20140715074628.GO15237@phenom.ffwll.local> (raw)
In-Reply-To: <1405365047-6866-13-git-send-email-tprevite@gmail.com>
On Mon, Jul 14, 2014 at 12:10:47PM -0700, Todd Previte wrote:
> The Displayport Link Layer Compliance Testing Specification 1.2 rev 1.1 specifies that
> repeated AUX transactions after a failure (NACK, DEFER or no response) must have
> a minimum delay of 400us before the resend can occur. Tests 4.2.1.1 and 4.2.1.2 are two
> tests that require this specifically.
>
> Signed-off-by: Todd Previte <tprevite@gmail.com>
Since this is a minimal timeout ... shouldn't we put it into the dp
helpers instead?
-Daniel
> ---
> drivers/gpu/drm/i915/intel_dp.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 0e207aaf..f0664cd 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -573,8 +573,12 @@ intel_dp_aux_ch(struct intel_dp *intel_dp,
> DP_AUX_CH_CTL_RECEIVE_ERROR);
>
> if (status & (DP_AUX_CH_CTL_TIME_OUT_ERROR |
> - DP_AUX_CH_CTL_RECEIVE_ERROR))
> + DP_AUX_CH_CTL_RECEIVE_ERROR)) {
> + /* DP compliance requires 400us delay for errors/timeouts
> + (DP CTS 1.2 Core Rev 1.1, 4.2.1.1 & 4.2.1.2) */
> + udelay(400);
> continue;
> + }
> if (status & DP_AUX_CH_CTL_DONE)
> break;
> }
> --
> 1.9.1
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
next prev parent reply other threads:[~2014-07-15 7:46 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-14 19:10 [PATCH v2] Displayport compliance testing Todd Previte
2014-07-14 19:10 ` [PATCH 01/12] drm/i915: Add automated testing support for " Todd Previte
2014-07-21 22:09 ` Paulo Zanoni
2014-07-30 14:49 ` Paulo Zanoni
2014-07-14 19:10 ` [PATCH 02/12] drm/i915: Add a function to compute the EDID checksum for Displayport compliance Todd Previte
2014-07-21 22:28 ` Paulo Zanoni
2014-07-14 19:10 ` [PATCH 03/12] drm/i915: Add counters in the drm_dp_aux struct for I2C NACKs and DEFERs Todd Previte
2014-07-21 22:37 ` Paulo Zanoni
2014-11-04 22:17 ` [PATCH 02/10] " Todd Previte
2014-11-04 22:26 ` Daniel Vetter
2014-07-14 19:10 ` [PATCH 04/12] drm/i915: Add wrapper function for intel_crtc_set_config() Todd Previte
2014-07-21 23:34 ` Paulo Zanoni
2014-07-14 19:10 ` [PATCH 05/12] drm/i915: Add a function to get the EDID preferred mode for Displayport compliance testing Todd Previte
2014-07-21 23:41 ` Paulo Zanoni
2014-07-14 19:10 ` [PATCH 06/12] drm/i915: Add a constant and function for getting the Displayport compliance failsafe video mode Todd Previte
2014-07-21 23:42 ` Paulo Zanoni
2014-07-14 19:10 ` [PATCH 07/12] drm/i915: Update EDID automated test function for Displayport compliance Todd Previte
2014-07-29 22:37 ` Paulo Zanoni
2014-07-31 18:27 ` Todd Previte
2014-07-14 19:10 ` [PATCH 08/12] drm/i915: Improve reliability for Displayport link training Todd Previte
2014-07-30 14:07 ` Paulo Zanoni
2014-07-30 15:25 ` Daniel Vetter
2014-07-14 19:10 ` [PATCH 09/12] drm/i915: Update intel_dp_check_link_status() for Displayport compliance testing Todd Previte
2014-07-30 14:29 ` Paulo Zanoni
2014-07-14 19:10 ` [PATCH 10/12] drm/i915: Update link training automated test function for Displayport compliance Todd Previte
2014-07-22 6:15 ` Daniel Vetter
2014-07-22 20:40 ` Jesse Barnes
2014-07-22 20:44 ` Daniel Vetter
2014-07-22 21:03 ` Jesse Barnes
2014-07-14 19:10 ` [PATCH 11/12] drm/i915: Minor code clean up in intel_dp.c Todd Previte
2014-07-15 7:47 ` Daniel Vetter
2014-07-15 15:35 ` Todd Previte
2014-07-14 19:10 ` [PATCH 12/12] drm/i915: Add a delay in Displayport AUX transactions for compliance testing Todd Previte
2014-07-15 7:46 ` Daniel Vetter [this message]
2014-07-15 15:34 ` Todd Previte
2014-07-30 14:46 ` Paulo Zanoni
2014-07-22 6:41 ` [PATCH v2] Displayport " Daniel Vetter
2014-07-22 20:48 ` Jesse Barnes
2014-07-22 20:53 ` Daniel Vetter
2014-07-22 21:11 ` Jesse Barnes
2014-07-29 21:53 ` Paulo Zanoni
2014-07-30 9:31 ` Daniel Vetter
2014-07-31 18:27 ` Todd Previte
2014-07-22 20:57 ` Jesse Barnes
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