> On 4 Aug 2018, at 11:54, Xin Li <delp...@delphij.net> wrote: > > Hi, Cy, > > On 8/3/18 12:11, Cy Schubert wrote: >> Author: cy >> Date: Fri Aug 3 19:11:00 2018 >> New Revision: 337271 >> URL: https://svnweb.freebsd.org/changeset/base/337271 >> >> Log: >> Some drives report a geometry that is inconsisetent with the total >> number of sectors reported through the BIOS. Cylinders * heads * >> sectors may not necessarily be equal to the total number of sectors >> reported through int13h function 48h. >> >> An example of this is when a Mediasonic HD3-U2B PATA to USB enclosure >> with a 80 GB disk is attached. Loader hangs at line 506 of >> stand/i386/libi386/biosdisk.c while attempting to read sectors beyond >> the end of the disk, sector 156906855. I discovered that the Mediasonic >> enclosure was reporting the disk with 9767 cylinders, 255 heads, 63 >> sectors/track. That's 156906855 sectors. However camcontrol and >> Windows 10 both report report the disk having 156301488 sectors, not >> the calculated value. At line 280 biosdisk.c sets the sectors to the >> higher of either bd->bd_sectors or the total calculated at line 276 >> (156906855) instead of the lower and correct value of 156301488 reported >> by int 13h 48h. >> >> This was tested on all three of my Mediasonic HD3-U2B PATA to USB >> enclosures. >> >> Instead of using the higher of bd_sectors (returned by int13h) or the >> calculated value, this patch uses the lower and safer of the values. >> >> Reviewed by: tsoome@ >> Differential Revision: https://reviews.freebsd.org/D16577 >> >> Modified: >> head/stand/i386/libi386/biosdisk.c >> >> Modified: head/stand/i386/libi386/biosdisk.c >> ============================================================================== >> --- head/stand/i386/libi386/biosdisk.c Fri Aug 3 18:52:51 2018 >> (r337270) >> +++ head/stand/i386/libi386/biosdisk.c Fri Aug 3 19:11:00 2018 >> (r337271) >> @@ -275,7 +275,7 @@ bd_int13probe(struct bdinfo *bd) >> >> total = (uint64_t)params.cylinders * >> params.heads * params.sectors_per_track; >> - if (bd->bd_sectors < total) >> + if (bd->bd_sectors > total) >> bd->bd_sectors = total; >> >> ret = 1; >> > > This broke loader on my system, but I think your reasoning was valid so > I took a deeper look and discovered that on my system, INT 13h, function > 48h would give zeros in EDD parameters' CHS fields. With that, the > calculated CHS based total would be 0, and your change would cause > bd_sectors be zeroed. > > Could you please let me know if https://reviews.freebsd.org/D16588 makes > sense to you? (I'm not 100% certain if I have followed the code). It > allowed my Asrock C2750D4I based board to boot from ZFS. >
I have in mind something a bit different for some time, but haven’t had chance to complete it because I have no “weird” systems to validate the idea:D I’ll try to get a bit of time and post an phabricator soon. rgds, toomas _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
