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From: "Hai Li" <hali@codeaurora.org>
To: "'Johansson, Werner'" <Werner.Johansson@sonymobile.com>,
	dri-devel@lists.freedesktop.org
Subject: RE: drm/msm/dsi Lane-swapping for 2-lane panels non-functional for msm8x74?
Date: Fri, 21 Aug 2015 16:14:09 -0400	[thread overview]
Message-ID: <005601d0dc4d$f157ccc0$d4076640$@codeaurora.org> (raw)
In-Reply-To: <3892D88DBE322D4FA4B7FE095FDA445A07C27BD1ACC4@seldmbx01.corpusers.net>

Hi Werner,

I will prepare a change to make the lane swap configurable.

Thanks,
Hai

-----Original Message-----
From: dri-devel [mailto:dri-devel-bounces@lists.freedesktop.org] On Behalf Of Johansson, Werner
Sent: Thursday, August 20, 2015 8:54 PM
To: dri-devel@lists.freedesktop.org
Subject: drm/msm/dsi Lane-swapping for 2-lane panels non-functional for msm8x74?

Hi,

I'm having issues with non-functional DSI output driving a 2-lane panel connected to DSI0 on MSM8x74 MDP5 v1.2 hardware. The code in drivers/gpu/drm/msm/dsi/dsi_host.c around line 703 enables lane 1 and 2 instead of lane 0 and 1 for performance reasons (and then enables lane swapping in the DSI PHY (LANE_SWAP_1230)). I cannot get this to work on the MSM8x74, no data observed on physical lane 0 (can't access lane1 easily unfortunately). Disabling this swap and enabling lane0 and 1 instead results in a fully functional panel.

Would it make sense to make this performance optimization a compile-time option that defaults to off (for certain problematic hardware or in general)?

/wj
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  reply	other threads:[~2015-08-21 20:14 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-21  0:54 drm/msm/dsi Lane-swapping for 2-lane panels non-functional for msm8x74? Johansson, Werner
2015-08-21 20:14 ` Hai Li [this message]
2015-08-21 20:23   ` Johansson, Werner
  -- strict thread matches above, loose matches on Subject: below --
2015-08-21 18:33 Johansson, Werner

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