Date: Sat, 24 Aug 2013 21:04:55 +0000 (UTC) From: Joerg Wunsch <joerg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r254809 - head/sys/dev/fdc Message-ID: <201308242104.r7OL4tUf068823@svn.freebsd.org>
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Author: joerg Date: Sat Aug 24 21:04:54 2013 New Revision: 254809 URL: http://svnweb.freebsd.org/changeset/base/254809 Log: Do not use "Enable Implied Seek" on enhanced floppy controllers. This breaks the "2step" feature of the driver, e.g. in order to read 360 KiB media on a 1200 KiB drive. As the only potential advantage of implied (vs. explicit) seeks is to minimize the software effort, yet our driver always contained the logic needed for explicit seeks, simply dropping implied seeks is the best solution without introducing risks for new bugs. There is no performance penalty, reading a 1440 KiB medium takes exactly the same time with both, implied or explicit seeks. MFC after: 1 week Modified: head/sys/dev/fdc/fdc.c Modified: head/sys/dev/fdc/fdc.c ============================================================================== --- head/sys/dev/fdc/fdc.c Sat Aug 24 21:00:39 2013 (r254808) +++ head/sys/dev/fdc/fdc.c Sat Aug 24 21:04:54 2013 (r254809) @@ -528,7 +528,8 @@ fdc_reset(struct fdc_data *fdc) if (fdc_cmd(fdc, 4, I8207X_CONFIG, 0, - 0x40 | /* Enable Implied Seek */ + /* 0x40 | */ /* Enable Implied Seek - + * breaks 2step! */ 0x10 | /* Polling disabled */ (fifo_threshold - 1), /* Fifo threshold */ 0x00, /* Precomp track */ @@ -922,14 +923,8 @@ fdc_worker(struct fdc_data *fdc) /* * SEEK to where we want to be - * - * Enhanced controllers do implied seeks for read&write as long as - * we do not need multiple steps per track. */ - if (cylinder != fd->track && ( - fdc->fdct != FDC_ENHANCED || - descyl != cylinder || - (bp->bio_cmd & (BIO_RDID|BIO_FMT)))) { + if (cylinder != fd->track) { retry_line = __LINE__; if (fdc_cmd(fdc, 3, NE7CMD_SEEK, fd->fdsu, descyl, 0)) return (1);
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