linux-kernel - Re: [PATCH v5 0/3] Decouple max_pclk check from constant display feats

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Message-ID: <670a6d68-3011-4241-a2f9-fd23373dcb43@ti.com>
Date: Thu, 28 Aug 2025 21:29:29 +0530
From: Swamil Jain <s-jain1@...com>
To: Michael Walle <mwalle@...nel.org>, <jyri.sarha@....fi>,
        <tomi.valkeinen@...asonboard.com>, <maarten.lankhorst@...ux.intel.com>,
        <mripard@...nel.org>, <tzimmermann@...e.de>, <airlied@...il.com>,
        <simona@...ll.ch>, <aradhya.bhatia@...ux.dev>
CC: <h-shenoy@...com>, <devarsht@...com>, <vigneshr@...com>, <praneeth@...com>,
        <u-kumar1@...com>, <dri-devel@...ts.freedesktop.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 0/3] Decouple max_pclk check from constant display
 feats



On 8/21/25 17:39, Michael Walle wrote:
> On Tue Aug 19, 2025 at 9:21 PM CEST, Swamil Jain wrote:
>> In an effort to make the existing compatibles more usable, we are
>> removing the max_pclk_khz form dispc_features structure and doing the
>> supported pixel clock checks using "max_successful_rate[]" and
>> "max_attempted_rate[]".
>>
>> 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_ext_vp_clk[] 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/
> 
> Since that wasn't picked up from v4:
> 
> Tested-by: Michael Walle <mwalle@...nel.org> # on am67a

Hi Michael,

Thanks for testing the patches. Sorry, I missed T-By.
Will add in v6.

Regards,
Swamil