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From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH v3 41/50] drm/bridge: ti-tfp410: Report input bus config through bridge timings
Date: Mon, 18 Mar 2019 02:00:37 +0200	[thread overview]
Message-ID: <20190318000037.GD12636@pendragon.ideasonboard.com> (raw)
In-Reply-To: <f19a7b94-e913-29a2-4935-8090613c6b4c@ti.com>

Hi Tomi,

On Fri, Mar 15, 2019 at 03:30:11PM +0200, Tomi Valkeinen wrote:
> On 15/03/2019 14:28, Peter Ujfalusi wrote:
> > On 15/03/2019 14.07, Tomi Valkeinen wrote:
> >>> If the pclk-sample is not defined in DT, it will default to 0 which
> >>> selects SAMPLE_NEGEDGE (== DRIVE_POSEDGE), right?
> >>>
> >>> But all the boards where I can find schematics with tfp410 have their
> >>> EDGE/HTPLG pin pulled up and according to the documentation when EDGE=1
> >>> then tfp410 will sample on the rising edge.
> >>>
> >>> imho the pclk_sample should be initialized to 1 to avoid regression for
> >>> most of the boards using tfp410.
> >>
> >> Define "regression" =). If the omapdrm driver was always using
> >> DRIVE_POSEDGE, this driver should also be using DRIVE_POSEDGE, no? If it
> >> does the same as the old driver, it can't be a regression. This is, of
> >> course, only considering omapdrm based boards.
> >>
> >> That said, it sounds odd that this would be wrong in the old driver, but
> >> then again, it might well be, as code related to these sync signals has
> >> changed sooo many times, and the related DSS registers are somewhat
> >> confusing.
> > 
> > On the boards data skew is enabled as well with maximum delay selected
> > with DK1=DK2=DK3=1, so sampling of data is delayed by 3 * 350 ps, so
> > about 1 ns, not much, but might be enough for the signal to transition
> > on the bus so even if the HW drivers on POSEDGE and tfp410 samples on
> > POSEDGE (+1ns delay from the edge) we don't see corruption?
> 
> Ok. I don't think anyone has looked at it that closely. So, the syncs
> could well be wrong. Still, not a regression if it's the same way as it was.
> 
> If the fixed default works fine (or better) than the wrong ones, I think
> that can be the default. But I'd be careful about changing what the
> default is, if we've had it the old way for a long time.

I don't object changing the default (given proper testing), but that
should be done on top of this series then.

-- 
Regards,

Laurent Pinchart
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  parent reply	other threads:[~2019-03-18  0:00 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-11  9:46 [PATCH v3 00/50] omapdrm: drm_bridge and drm_panel support Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 01/50] drm/atomic: Constify mode argument to mode_valid_path() Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 02/50] drm/omap: dsi: Fix crash in DSI debug dumps Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 03/50] drm/omap: dsi: Fix OF platform depopulate Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 04/50] drm/omap: dsi: Hack-fix DSI bus flags Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 05/50] drm/omap: Remove declaration of nonexisting function Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 06/50] drm/omap: Remove unused kobj field from struct omap_dss_device Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 07/50] drm/omap: venc: Remove wss_data field from venc_device structure Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 08/50] drm/omap: Use atomic suspend/resume helpers Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 09/50] drm/omap: Move common display enable/disable code to encoder Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 10/50] drm/omap: Remove connection checks from internal encoders .enable() Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 11/50] drm/omap: Remove connection checks from display .enable() and .remove() Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 12/50] drm/omap: Remove enable " Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 13/50] drm/omap: Reverse direction of the DSS device enable/disable operations Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 14/50] drm/omap: Remove omap_dss_device dst field Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 15/50] drm/omap: Factor out common init/cleanup code for output devices Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 16/50] drm/omap: Expose DRM modes instead of timings in display devices Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 17/50] drm/omap: Merge display .get_modes() and .get_size() operations Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 18/50] drm/omap: Add a dss device operation flag for .get_modes() Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 19/50] drm/omap: venc: List both PAL and NTSC modes Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 20/50] drm/omap: Don't pass display pointer to encoder init function Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 21/50] drm/omap: Move display alias ID to omap_drm_pipeline Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 22/50] drm/omap: Don't store display pointer in omap_connector structure Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 23/50] drm/omap: panel-dsi-cm: Store source pointer internally Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 24/50] drm/omap: Notify all devices in the pipeline of output disconnection Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 25/50] drm/omap: Remove src field from omap_dss_device structure Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 26/50] drm/omap: Move DISPC timing checks to CRTC .mode_valid() operation Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 27/50] drm/omap: venc: Simplify mode setting by caching configuration Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 28/50] drm/omap: Factor out common mode validation code Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 29/50] drm/omap: Pass drm_display_mode to .check_timings() and .set_timings() Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 30/50] drm/omap: venc: Use drm_display_mode natively Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 31/50] drm/omap: Store pixel clock instead of full mode in DPI and SDI encoders Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 32/50] drm/omap: Simplify OF lookup of DSS devices Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 33/50] drm/omap: Refactor initialization sequence Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 34/50] drm/omap: Merge omap_dss_device type and output_type fields Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 35/50] drm: Clarify definition of the DRM_BUS_FLAG_(PIXDATA|SYNC)_* macros Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 36/50] drm: Use new DRM_BUS_FLAG_*_(DRIVE|SAMPLE)_(POS|NEG)EDGE flags Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 37/50] drm/bridge: use bus flags in bridge timings Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 38/50] dt-bindings: display: tfp410: Add bus parameters properties Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 39/50] drm/bridge: ti-tfp410: Set connector type based on DT connector node Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 40/50] drm/bridge: ti-tfp410: Add support for the powerdown GPIO Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 41/50] drm/bridge: ti-tfp410: Report input bus config through bridge timings Laurent Pinchart
2019-02-28 10:27   ` Tomi Valkeinen
2019-02-28 10:31     ` Tomi Valkeinen
2019-03-15 11:30       ` Peter Ujfalusi
2019-03-15 12:07         ` Tomi Valkeinen
2019-03-15 12:28           ` Peter Ujfalusi
2019-03-15 13:30             ` Tomi Valkeinen
2019-03-15 14:04               ` Peter Ujfalusi
2019-03-18  0:00               ` Laurent Pinchart [this message]
2019-02-11  9:46 ` [PATCH v3 42/50] dt-bindings: Add vendor prefix for OSD Displays Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 43/50] dt-bindings: display: Add OSD Displays OSD070T1718-19TS panel binding Laurent Pinchart
2019-02-11  9:46 ` [PATCH v3 44/50] drm/panel: simple: Add OSD070T1718-19TS panel support Laurent Pinchart
2019-02-11  9:47 ` [PATCH v3 45/50] drm/omap: Add support for drm_bridge Laurent Pinchart
2019-02-11  9:47 ` [PATCH v3 46/50] drm/omap: Add support for drm_panel Laurent Pinchart
2019-02-11  9:47 ` [PATCH v3 47/50] drm/omap: Whitelist DT nodes to fixup with omapdss, prefix Laurent Pinchart
2019-02-11  9:47 ` [PATCH v3 48/50] drm/omap: Remove TFP410 and DVI connector drivers Laurent Pinchart
2019-02-11  9:47 ` [PATCH v3 49/50] drm/omap: Remove panel-dpi driver Laurent Pinchart
2019-02-11  9:47 ` [PATCH v3 50/50] drm: Turn bus flags macros into an enum Laurent Pinchart

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