On Mon, Jan 24, 2011 at 04:39:21PM -0000, Pawel Moll wrote:
Well, fixing MMCI because ISP1761 is buggy is not the way forward. The answer is to fix the broken ISP1761 driver.
Totally agree. The thing is that you are the only person right now who doesn't have any problems.
That's not my problem. A simple search of the linux-usb mailing list will give you the patch:
http://marc.info/?l=linux-usb&m=129469114904445&w=2
The others can quickly benefit from the workaround.
Others _can_ quickly benefit from the ISP1761 fix by applying the above patch, which not only fixes the MMCI overruns, but also allows USB to serial devices to work with Versatile Express. The above patch is the correct solution.
For christ sake, that patch is a fix for a *known* errata issued by the ISP1761 manufacturer.
Well as I see it, it's pointless enlarging the FIFO. ARM Ltd isn't going to give me updated FPGA images for the Integrator/CP, Versatile PB926, Realview EB and Versatile Express.
If we succeed with this, you (and all other users) will get the "improved" FPGA image. But for VE only indeed.
That's utterly useless and completely pointless.
Look, stop jumping off a cliff with this and come back to reality. The ISP1761 is buggy. We have a fix. We have a tested fix. We have a tested fix out on mailing lists for everyone to use. It fixes more than MMC overruns and makes the ISP1761 usable.
The only problem is that it's taking *FAR* too long for it to get into mainline for no apparant reason. That doesn't stop anyone taking the tested patch in the URL above and gaining proper USB functionality.
The right thing to do is to follow up on my reply on the ISP1761 thread to find out why it's taking soo long for it to get into Linus' tree.
I repeat, with the proper set of patches in mainline THERE IS NO ISSUE WITH MMCI. THE HARDWARE DOES NOT NEED "FIXING". Please listen to me.
My final mail on this subject. I'm adding Philippe and Catalin so that they're in the loop on this.
Take a mainline kernel. Apply the attached three patches. MMC will then work without any problems. No hacks required. There is *absolutely* *no* need to waste time with hardware modifications.
With this you will find that MMCI FIFO underruns/overruns are no longer any problem.
My final mail on this subject.
Ah, and I was really enjoying our pleasant discussion...
Take a mainline kernel. Apply the attached three patches. MMC will then work without any problems. No hacks required. There is *absolutely* *no* need to waste time with hardware modifications.
With this you will find that MMCI FIFO underruns/overruns are no longer any problem.
$ git log -1 commit d315777b32a4696feb86f2a0c9e9f39c94683649 Merge: 5a05a6d 1765e3a Author: Linus Torvalds torvalds@linux-foundation.org Date: Mon Jan 24 19:58:39 2011 +1000 [...] $ git diff > changes.diff
Attached, I trust you will find all your changes there (and only them).
/ # uname -a Linux (none) 2.6.38-rc2+ #11 SMP Mon Jan 24 17:11:35 GMT 2011 armv7l GNU/Linux / # cat /dev/sda > /dev/null & / # dd if=/dev/mmcblk0 of=/dev/null bs=64k count=128 dd: /dev/mmcblk0: Input/output error
And dmesg is full of: [...] mmcblk0: error -5 transferring data, sector 254, nr 2, cmd response 0x900, card status 0xb00 end_request: I/O error, dev mmcblk0, sector 254 mmcblk0: error -5 transferring data, sector 255, nr 1, cmd response 0x900, card status 0xb00 end_request: I/O error, dev mmcblk0, sector 255 mmcblk0: error -5 transferring data, sector 0, nr 8, cmd response 0x900, card status 0x900 mmcblk0: retrying using single block read mmcblk0: error -5 transferring data, sector 0, nr 8, cmd response 0x900, card status 0xb00 [...]
Now:
$ git am 0001-arm-Improve-MMC-performance-on-Versatile-Express.patch
/ # uname -a Linux (none) 2.6.38-rc2+ #12 SMP Mon Jan 24 17:41:53 GMT 2011 armv7l GNU/Linux / # cat /dev/sda > /dev/null & / # dd if=/dev/mmcblk0 of=/dev/null bs=64k count=128 128+0 records in 128+0 records out 8388608 bytes (8.0MB) copied, 1.501529 seconds, 5.3MB/s
THERE IS NO ISSUE WITH MMCI. THE HARDWARE DOES NOT NEED "FIXING".
I'm really pleased you think so. It's always nice to have happy customers :-)
Cheers!
Paweł
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Pawel Moll -
Russell King - ARM Linux