From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr1-x429.google.com (mail-wr1-x429.google.com [IPv6:2a00:1450:4864:20::429]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2107B6E943 for ; Wed, 14 Apr 2021 15:24:44 +0000 (UTC) Received: by mail-wr1-x429.google.com with SMTP id x7so20257280wrw.10 for ; Wed, 14 Apr 2021 08:24:44 -0700 (PDT) Date: Wed, 14 Apr 2021 17:24:40 +0200 From: Daniel Vetter Message-ID: References: <20210409193048.6857-1-bhanuprakash.modem@intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Subject: Re: [igt-dev] [PATCH i-g-t 0/5] Fix mode selection for 2x tests List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: igt-dev-bounces@lists.freedesktop.org Sender: "igt-dev" To: "Modem, Bhanuprakash" Cc: IGT development List-ID: On Mon, Apr 12, 2021 at 03:51:40AM +0000, Modem, Bhanuprakash wrote: > > From: Daniel Vetter > > Sent: Saturday, April 10, 2021 1:48 AM > > To: Modem, Bhanuprakash > > Cc: IGT development > > Subject: Re: [igt-dev] [PATCH i-g-t 0/5] Fix mode selection for 2x tests > > > > On Fri, Apr 9, 2021 at 1:39 PM Bhanuprakash Modem > > wrote: > > > > > > When two monitors connected through MST, the second monitor also > > > tries to use the same mode. So two such modes may not fit into the > > > link bandwidth. > > > > > > This series will find a combination of modes that fit into the BW. > > > > > > By parsing the PATH property, we can add a link_group_id field to > > > igt_output_t to identify all connectors that shares the BW of the > > > same link. > > > > > > Parsing the PATH property consists of finding all connectors with > > > the same X prefix in the X-Y[-Z...] path property format and assigning > > > a unique non-zero link_group_id to all such connectors. Connectors > > > without a PATH property are not an MST output, so their link_group_id > > > can be left at 0. > > > > > > IGT core helper would override the mode on all connectors that will > > > be modeset by the next igt_display_commit() call in the test. These > > > are all the connectors in igt_display_t that have a pending_pipe set > > > by the test up to the point of calling this helper. > > > > > > Signed-off-by: Bhanuprakash Modem > > > > Uh this is really not how kms is supposed to work. There are _tons_ of > > reasons why 2 crtc at the same time wont work, mst bw constraint is > > just one. > > > > If you want to fix this, this should be fixed with atomic TEST_ONLY > In fact, we are doing the same in this series. > > By parsing the PATH connector prop, igt_output_refresh() will update the > link_group_id field for each connector [1]. > > Each individual (Nx)-test will identify the connectors those are sharing > the MST bw (by reading the link_group_id field in igt_output_t), and call > the helper to find the suitable modes [2]. > > A helper function iterates through those N output/mode combinations. And > find the combination using the most BW by ATOMIC_TEST_ONLY and returned > to the test [3]. > > Am I missing anything? Using TEST_ONLY sounds good. Trying to do clever filtering with PATH property before you call TEST_ONLY is not good. You should check with TEST_ONLY in general, not just when the path property indicates that the dp output is shared. -Daniel > > [1]: https://patchwork.freedesktop.org/patch/427718 > [2]: https://patchwork.freedesktop.org/patch/427720 > [3]: https://patchwork.freedesktop.org/patch/427719 > N : 2,3,4,... > > -Bhanu > > mode to figure out what works and what doesn't. Not by trying to > > re-implement the kernel's atomic_check configuration validation, > > because you just can't do that. > > > > So nack on architectural reasons on this approach. > > -Daniel > > > > > > > > Bhanuprakash Modem (5): > > > lib/igt_kms: Add a support to read PATH connector property > > > lib/igt_kms: Identify outputs that shares link bandwidth > > > lib/igt_kms: helper to override the mode on all connectors > > > tests/kms_frontbuffer_tracking: Fix mode selection for 2x tests > > > tests/kms_cursor_legacy: Fix mode selection for 2x tests > > > > > > lib/igt_kms.c | 71 ++++++++++++++++++++++++++++++++ > > > lib/igt_kms.h | 3 ++ > > > tests/kms_cursor_legacy.c | 53 ++++++++++++++++++++++-- > > > tests/kms_frontbuffer_tracking.c | 35 ++++++++++++++++ > > > 4 files changed, 159 insertions(+), 3 deletions(-) > > > > > > -- > > > 2.20.1 > > > > > > _______________________________________________ > > > igt-dev mailing list > > > igt-dev@lists.freedesktop.org > > > https://lists.freedesktop.org/mailman/listinfo/igt-dev > > > > > > > > -- > > Daniel Vetter > > Software Engineer, Intel Corporation > > http://blog.ffwll.ch -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ igt-dev mailing list igt-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/igt-dev