Date: Fri, 22 Apr 2016 11:05:50 -0600 From: Warner Losh <imp@bsdimp.com> To: John Baldwin <jhb@freebsd.org> Cc: Hans Petter Selasky <hps@selasky.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r298426 - head/sys/dev/fdc Message-ID: <6FBAFEC9-B22D-407A-A2DB-D0B37D519E57@bsdimp.com> In-Reply-To: <4396944.pMOIsoy4We@ralph.baldwin.cx> References: <201604211837.u3LIbalm092252@repo.freebsd.org> <57191F7F.4010900@selasky.org> <4396944.pMOIsoy4We@ralph.baldwin.cx>
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[-- Attachment #1 --] > On Apr 22, 2016, at 10:43 AM, John Baldwin <jhb@freebsd.org> wrote: > > On Thursday, April 21, 2016 08:44:15 PM Hans Petter Selasky wrote: >> On 04/21/16 20:37, John Baldwin wrote: >>> - tsleep(fdc, PRIBIO, "fdcrst", hz); >>> + if (cold) >>> + DELAY(1000000); >>> + else >>> + tsleep(fdc, PRIBIO, "fdcrst", hz); >> >> Hi, >> >> pause() and pause_sbt() does exactly this, checking for "cold" and using >> DELAY(). > > Yes, I know. In theory though the driver interrupt could fire during > normal operation aborting the sleep, so the wait channel for the !cold > case is actually there for a reason it seems. (That is, in the !cold case > the driver might terminate the sleep early which you can't do with pause.) Most of the sleeps in the fdc driver are more of a timeout waiting for the interrupt to fire sorts of things. Post an action to the drive, and tsleep for a second or until that action is done and you can get on with the next thing. I’ll admit to being lazy and not checking this specific one, but it’s a general design pattern in this driver... Warner [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJXGlnvAAoJEGwc0Sh9sBEA9vsP/RmTVZy2U/fxgYHsnR89KxF7 SdkYENBKQz0USTznb/lv/ObsYDW9RxvVhtWbeyNJ+uvGb4ghOYrnbJuHhe0XHCZ9 0zotRQSKtkBM5F0RFNz9TYjBZfd2EsqTF7Nn0AU895yGKQIl0/MfOpP2XykvuvGs WyDKZF6mXQr5eQTjtL80EZb+StAn2rg0BwmbShrfsad6MwfcRYJ5chzliENpUc+y ULcsfzr/Dmwpa/LnR88JHK9IqXWKNWWgm4xmiOkRUa6yJf3CKUSkhD9Eoz7CV8gg nX+1am+yrqDJiB3W6ufE6wdWO4i0eBStnUuRJgJQfJsceNciNmIw0fv14atutV50 Ro+rEOgzSmxScuocQiU8ruxUcVPRyq5awMW05kwX4+hp3JjBmQwmo8EYB6TB0Hcn 74pNZnYKuVDqyzFpNojEwO0qmo2Y0tkg8fQO3D0e63a2/R4zQwPtk9vN0zSenB21 XaNKQjocvE5F2HZ4bRI/rbe6jntFgtNyPZ7EZDTQkymzr7TZEyxdfFTKq5f3CHwg xnMGKZ5lGRN5WiVYDmQE9GfdZZI4y6soC6tw/7NgDl2tNfwYLW56PV1SpS5Ova5i Mpfse1A3+IOLcz3oz2v4nRcNXHWc7D6LNXrUlOeuPjdKUrDtRcWeJr2HwhYYxOxE 7vVKLuoWLnvX7APFA2gP =RTJj -----END PGP SIGNATURE-----
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