Date: Tue, 30 Apr 2019 11:53:42 -0400 From: Tycho Nightingale <tycho@pobox.com> To: Warner Losh <imp@bsdimp.com> Cc: Hans Petter Selasky <hps@selasky.org>, Niclas Zeising <zeising@freebsd.org>, src-committers <src-committers@freebsd.org>, svn-src-all <svn-src-all@freebsd.org>, svn-src-head <svn-src-head@freebsd.org> Subject: Re: svn commit: r346958 - head/sys/compat/linuxkpi/common/src Message-ID: <7927F561-6922-4960-90EC-BD36E0190A6F@pobox.com> In-Reply-To: <CANCZdfqV5BPcQx0iC7wpvttmvxwyfEkb7XQVrRMPp2Jk_bqYTQ@mail.gmail.com> References: <201904301041.x3UAfLvj054368@repo.freebsd.org> <8f360678-2df1-fe7b-cb83-f47923534826@freebsd.org> <2f77d9f2-833d-f614-e193-a369086c01cf@selasky.org> <CANCZdfqV5BPcQx0iC7wpvttmvxwyfEkb7XQVrRMPp2Jk_bqYTQ@mail.gmail.com>
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> On Apr 30, 2019, at 11:24 AM, Warner Losh <imp@bsdimp.com> wrote: >=20 >=20 > On Tue, Apr 30, 2019 at 9:17 AM Hans Petter Selasky <hps@selasky.org = <mailto:hps@selasky.org>> wrote: > On 4/30/19 3:10 PM, Niclas Zeising wrote: > > On 2019-04-30 12:41, Hans Petter Selasky wrote: > >> Author: hselasky > >> Date: Tue Apr 30 10:41:20 2019 > >> New Revision: 346958 > >> URL: https://svnweb.freebsd.org/changeset/base/346958 = <https://svnweb.freebsd.org/changeset/base/346958>; > >> > >> Log: > >> Reduce the number of mutexes after r346645 in the LinuxKPI. > >> Make function macro wrappers for locking and unlocking to ease=20= > >> readability. > >> No functional change. > >> Discussed with: kib@, tychon@ and zeising@ > >=20 > > I was not part of any discussion regarding this. If this is related = to=20 > > https://reviews.freebsd.org/D20097 = <https://reviews.freebsd.org/D20097>; I explicitly asked you on gitter to=20= > > hold of for a bit, while we try to figure out why we are seeing=20 > > regressions in graphics with the latest dmar changes. > >=20 > > Can you please revert this since it colludes the dmar graphics = issue,=20 > > and it makes the suggested patch not apply cleanly, which makes it=20= > > harder to get people to help test. > > Thank you! > > Regards >=20 > In response to your request I've collected fixes for all the known=20 > LinuxKPI+DMA issues at: > https://reviews.freebsd.org/D20097 = <https://reviews.freebsd.org/D20097>; >=20 > It is based on top of the latest -current. >=20 > Hopefully this will solve the problem. Do you have any idea of when we = might see resolution of this issue? I'd like to see it fixed by Friday = either with fixes or a revert. Do you think that's a reasonable time = frame? If not, what do you think a reasonable time frame will be? I know = we have a number of unknowns to factor in, so my queries are based on = our best guesses. Friday seems reasonable. The issues that have been exposed are that several callers of the Linux = API are not compliant with the documented API. For example according to = the documentation, dma_map_sg() may coalesce entries and our current = implementation does that. This broke some graphics drivers. To support = these drivers, going back to the non-coalesced version is the only path = forward as the callee bugs redefine this API de facto; this is included = in D20097. Also included in D20097 is a fix to ensure sg_dma_len() is equal to = sg->length =E2=80=94 again to address assumptions in drivers. Finally, apparently some drivers load the same DMA address multiple = times without any prior unload. Those drivers need to work too; D20097 = contains a fix. Thanks hps@ for helping out! Tycho=
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