On Thu, Jan 07, 2010 at 07:28:55PM -0700, Gomez, Camilo F wrote: > How do you turn this on? > Do I need to recompile kernel with this flag? Or is it simply an environment variable? > Please send me more details how to turn it on :) You might need to recompile your kernel. It's under Device Drivers-> USB support-> USB verbose debug messages. Most distros have this kernel config option turned on by default. Along with dmesg, it's also useful to follow the directions for the USB monitor (USB mon) in Documentation/usb/usbmon.txt of the Linux kernel source tree. You can find an online version of the file here: http://www.mjmwired.net/kernel/Documentation/usb/usbmon.txt I'm moving this discussion to the linux-usb mailing list, since the other Linux USB developers might remember a know bug/work around. Sarah Sharp > -----Original Message----- > From: Sharp, Sarah A > Sent: Thursday, January 07, 2010 3:00 PM > To: Gomez, Camilo F > Cc: Gross, Mark; > Subject: Re: SD card write speed slow in Ubuntu 9.10 x86_64 but its fine on 8.04.3TLS i386. > > Can both of you turn on CONFIG_USB_DEBUG and send the dmesg to the > linux-usb@xxxxxxxxxxxxxxx mailing list? It sounds like you might have a > USB problem. > > Sarah Sharp > > On Wed, Jan 06, 2010 at 12:32:08PM -0800, Gomez, Camilo F wrote: > > I am experiencing similar issues. Writes to uSD cards sometimes go really fast 35MB/s all the way. Sometimes it starts fast and then it slows down to less than 300KB/s making it very painful to create recreate multi gigabyte file systems. I experience this doing dd or uncompressing a tarball to the device. > > > > I have different USB card readers and all do the same. However, I only have uSD cards from SanDisk. I experience this issue with FC9/11 x86 and openSUSE 11.2 x86_64 > > > > Camilo > > > > -----Original Message----- > > Sent: Wednesday, January 06, 2010 1:12 PM > > Subject: [Intel-linux] SD card write speed slow in Ubuntu 9.10 x86_64 but its fine on 8.04.3TLS i386. > > > > Its really bad on my new 64 bit installation, and the writes seem to fail after taking hrs. > > The system is a Compaq 8510w laptop. > > > > I'm using the same USB2.0 to SD dongle and same 4 gig SD card on both systems. > > > > I use them to create SD cards with a moblin root file system image, its about 1.5Gig of bits that get written. > > > > On the old system it finishes in about 20min and the new one never finishes but tries and tries for 2hrs before it sporadically remounts the SD and fails the cp -a operation, or it claims to finish but fails to work. > > > > Anyone else have experience with the SD cards on the newer distros in 64 bit mode or any comments? > > > > Thanks, > > > > --mross -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
