Date: Mon, 25 Feb 2019 08:21:48 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 235944] jedec_dimm(4) does not attach to KFA2 (aka Galax) Hall of Fame DDR4 sticks Message-ID: <bug-235944-227-7UizEJEBHc@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-235944-227@https.bugs.freebsd.org/bugzilla/> References: <bug-235944-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D235944 --- Comment #14 from Andriy Gapon <avg@FreeBSD.org> --- (In reply to Ravi Pokala from comment #13) Oh, I recall this now. Thank you for refreshing my memory. And I could ha= ve checked the code more thoroughly myself. So, sorry for the noise. In one part-specific datasheet I noticed this curious bit: https://www.onsemi.com/pub/Collateral/N34C04-D.PDF > 17. The N34C04MU3ETG will respond with NoACK following the dummy Data Byt= e, > while the N34C04MU3EKTG will respond with ACK. Maybe that NoACK (NACK) is what we are seeing here as an SMBus error. Although the code mapped PIIX4_SMBHSTSTAT_ERR | PIIX4_SMBHSTSTAT_INTR to SMB_EBUSERR rather than to SMB_ENOACK, I am not sure if that mapping is (universally) correct. E.g., in one AMD BKDG document I see this: > Bits Description > 2 DeviceErr. Read; Write-1-to-clear; Set-by-hardware. > Reset: 0. > 1=3DAn error of one of the following occurred: > =E2=80=A2 Illegal command field. > =E2=80=A2 Unclaimed cycle > =E2=80=A2 Host device time-out. > 1 SMBusInterrupt. Read; Write-1-to-clear; Set-by-hardware. > Reset: 0. 1=3DCompletion of the last host command. A combination of these bits can mean an "unclaimed cycle" and maybe that me= ans "NACK" in the SMBus protocol terminology. So, it would be interesting to see - what specific EEPROM part the DIMM in question uses (a looking glass can help) - what happens if we ignore the error from the page change write --=20 You are receiving this mail because: You are the assignee for the bug.=
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