Ole Holm Nielsen 2008-03-28 10:19:20 EDT Description of problem: The built-in SATA hard disk of the HP dc7800 desktop PC (with Intel Q35 Express chipset) is incorrectly configured, and disk I/O performance is more than 10 times lower than it should be. Users experience a very slow system. We test I/O performance by writing a large file to disk: # time dd if=/dev/zero of=temp bs=1024k count=50000 bytes (5.2 GB) copied, 978.086 seconds, 5.4 MB/s Another symptom of the problem is that DMA is turned off (and cannot be turned on): # hdparm -d /dev/hda using_dma = 0 (off) The fact that the disk is denoted as /dev/hda in stead of the expected /dev/sda is yet another symptom of the problem.

We have installed Fedora Core 9 on the same hardware. FC9 detects the hard disk as /dev/sda, and writing a big file as above gives a disk I/O speed of 55-60 MB/sec. We have also built and installed the kernel.org Linux kernel version 2.4.26.2 on the RHEL 5.2 system, and this kernel fixes the problem as well.

Download the latest software & drivers for your HP Compaq dc7800 Small Form Factor PC. 'EliteBook 840 G3 bios update. HP is aware of the recent.

Conclusion: The RHEL kernel 2.6.18-84.el5 (and older) doesn't support the Intel Q35 Express chipset correctly. The solution would seem to be backporting the support of Intel Q35 Express from later Linux kernels. Version-Release number of selected component (if applicable): RHEL 5.2 Beta (and any previous version) How reproducible: Always Steps to Reproduce: 1. Install RHEL onto HP dc7800 desktop PC 2. Test hard disk I/O performance 3. Actual results: I/O performance is about 5 MB/sec.

SATA disk device is /dev/hda. Expected results: I/O performance should be above 50 MB/sec. SATA disk device is /dev/sda.

Solved: Can i update BIOS? I am using HP Compaq small form factor dc7800 - 6012115. How to perform a HP BIOS upgrade with only Ubuntu? Or cabextract to unpack HP's BIOS update packages. Unix & Linux; Ask Different. Athletic Works Owners Manual there. Review options to update your HP printer. 'EliteBook 840 G3 bios update' Search. As all major Linux distributions regularly integrate HP Linux Imaging and.

Additional info: The HP dc7800 desktop PC is Certified and Supported by RedHat, see Workaround: Install newer Linux kernel or Fedora Core. Elsawin Seat Data Dvd Player there. Ole Holm Nielsen 2008-03-31 05:54:35 EDT Firstly, I was advised in to use the kernel parameter pci=nommconf in stead of pci=conf1. Either of these boot flags seem to work well on the dc7800 hardware.

I tested booting the dc7800 with RHEL 5.2 Beta using the kernel.org Linux kernel 2.4.26.2 *without* pci=nommconf. In this case the boot freezes after a couple of seconds just after the 'Booting the kernel' message. Apparently the kernel.org people didn't provide boot support for the Intel Q35 Express chipset (or it needs a special kernel config). When using the pci=nommconf flag, disk I/O performance is great with kernel 2.4.26.2 (55-60 MBytes/sec), and it's still abysmal with the RHEL 5.2 kernel (5 MBytes/sec). Ole Holm Nielsen 2008-04-01 03:45:37 EDT I checked the HP dc7800 BIOS setup now: The default settings are used in my case, and in the notation that the HP BIOS uses the following settings are made: SATA Defaults: Multisector transfers: 16 Transfer mode: Max UDMA Translation mode: Automatic SATA0 160 GB SATA hard disk: Emulation type: hard disk Multisector transfers: 16 Translation mode: Automatic Even though AHCI isn't mentioned anywhere in the BIOS, I trust that HP has implemented the maximum performance settings for the SATA disks. Ole Holm Nielsen 2008-04-01 15:21:32 EDT Bryan, the system operates at native speed ONLY with kernel 2.6.24.2 from kernel.org, NOT with any RHEL kernels!