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Created attachment 486869 [details] mmc_add_support_for_cmd25.patch Description of problem: When we transfer a large file ~600M to the SDSC card, and then try to unmount the card, the unmounting takes a long time (~25 mins) to complete. The test platform is AMD Cobia which has SD2.0 controller. Version-Release number of selected component (if applicable): How reproducible: Always. Steps to Reproduce: 1. Default install RHEL5.5 i386/x86_64. 2. Insert an SDSC card into the slot. 3. Mount manually if not auto-mounted. 4. Time the copy and umount command on the same line, eg: time cp xxx /mnt/tmp; time umount /mnt/tmp Actual results: It takes ~25 mins to transfer ~600M file. Expected results: The data transfer should complete sooner. Additional info: The current SDHC code in RHEL5.5 does SDMA rather than ADMA2 used by recent kernels. If we disable ADMA2 and enable SDMA, the data transfer rate is still faster for newer kernels than RHEL5.5 kernel-2.6.18-194.el5.
=== In Red Hat Customer Portal Case 00440374 === --- Comment by Nath, Arindam on 3/22/2011 2:08 AM --- Root Cause: The current mmc code doesn't support CMD25. The result is that larger file transfers take a long amount of time to complete.
=== In Red Hat Customer Portal Case 00440374 === --- Comment by Nath, Arindam on 3/22/2011 2:11 AM --- The current mmc code doesn't support CMD25. The result is that larger file transfers take a long amount of time to complete. This patch adds support for CMD25, improving the data transfer rate significantly. Comparing the results of the patched and default kernels, the same data transfer of ~600M file takes ~4 mins with the patched kernel. Thanks, Arindam
=== In Red Hat Customer Portal Case 00440374 === --- Comment by Nath, Arindam on 3/22/2011 2:13 AM --- Hello, Even though the description talks about reproducing the issue on RHEL5.5, the same applies to RHEL5.6 too. Thanks, Arindam
=== In Red Hat Customer Portal Case 00440374 === --- Comment by Nath, Arindam on 3/22/2011 2:20 PM --- Hello Joe, Yes, we have confirmed that this patch fixes the said issue. The patch is already part of kernel upstream. Please refer to commit db53f28b3a6d9338cca1b7e917dc063ac99e1871. Thanks, Arindam
Hello, This appears to be a duplicate of BZ: https://bugzilla.redhat.com/show_bug.cgi?id=655771 I am closing as a dup. Thank You Joe Kachuck *** This bug has been marked as a duplicate of bug 655771 ***