linux-kernel - Re: [PATCH v4 0/3] Decouple max_pclk check from constant display feats

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Message-ID: <c638ebecd9b01df5779d3f8931c2bf17@kernel.org>
Date: Fri, 18 Jul 2025 12:08:34 +0200
From: Michael Walle <mwalle@...nel.org>
To: Jayesh Choudhary <j-choudhary@...com>
Cc: jyri.sarha@....fi, maarten.lankhorst@...ux.intel.com,
 mripard@...nel.org, tzimmermann@...e.de, dri-devel@...ts.freedesktop.org,
 devarsht@...com, tomi.valkeinen@...asonboard.com, airlied@...il.com,
 simona@...ll.ch, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 0/3] Decouple max_pclk check from constant display
 feats

> In an effort to make the existing compatibles more usable, we are
> removing the max_pclk_khz form dispc_features structure and doing the
> correspondig checks using "curr_max_pclk[]".
> 
> Changes are fully backwards compatible.
> 
> After integration of OLDI support[0], we need additional patches in
> oldi to identify the VP that has OLDI. We have to do this since
> OLDI driver owns the VP clock (its serial clock) and we cannot perform
> clock operations on those VP clock from tidss driver. This issue was
> also reported upstream when DSI fixes[1] had some clock related calls
> in tidss driver. When "clk_round_rate()" is called, ideally it should
> have gone to "sci_clk_determine_rate()" to query DM but it doesn't 
> since
> clock is owned by OLDI not tidss.
> 
> So add a member is_oldi_vp[] in tidss_device structure to identify this
> and avoid performing clock operations for VP if it has OLDI panel.
> For the same checks in OLDI driver, atomic_check() hook is added to its
> bridge_funcs.
> In the atomic_check() chain, first the bridge_atomic_check() is called
> and then crtc_atomic_check() is called. So mode clock is first checked
> in oldi driver and then skipped in tidss driver.
> 
> Had the tidss_oldi structure been exposed to tidss_dispc.c, we could
> have directly checked VP type in dispc but since the structure is 
> defined
> in tidss_oldi.c , we have to add additional member to tidss_device
> structure.
> 
> [0]: 
> https://lore.kernel.org/all/20250528122544.817829-1-aradhya.bhatia@linux.dev/
> [1]: https://lore.kernel.org/all/DA6TT575Z82D.3MPK8HG5GRL8U@kernel.org/

For this series:
Tested-by: Michael Walle <mwalle@...nel.org> # on am67a

-michael