From mboxrd@z Thu Jan 1 00:00:00 1970 From: hemanthv@ti.com (Hemanth V) Date: Thu, 18 Mar 2010 20:11:01 +0530 Subject: Highmem issues with MMC filesystem References: <037201cac5d7$6c5b8c60$LocalHost@wipblrx0099946> <043e01cac5df$c3ec1b90$LocalHost@wipblrx0099946> <20100318092352.GD8267@n2100.arm.linux.org.uk> <20100318112453.GA19544@n2100.arm.linux.org.uk> <20100318141930.GF19544@n2100.arm.linux.org.uk> Message-ID: <0b0f01cac6a9$0a8b8990$LocalHost@wipblrx0099946> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org ----- Original Message ----- From: "Russell King - ARM Linux" To: "Shilimkar, Santosh" Cc: "Nicolas Pitre" ; ; "V, Hemanth" ; "saeed bishara" ; ; Sent: Thursday, March 18, 2010 7:49 PM Subject: Re: Highmem issues with MMC filesystem > On Thu, Mar 18, 2010 at 07:00:06PM +0530, Shilimkar, Santosh wrote: >> Or could it be that there is appropriate cacheflush happening but data >> gets >> stuck in CPU writebuffers instead of reaching to main memory. In this >> case >> too DMA won't see the contents and a barrier (dsb) is necessary to ensure >> that write buffer is drained before DMA takes over the buffer. > > That would imply that the data on the device is becoming corrupted. > > What exactly is the problem that we're discussing? Is it that the data > on the block device is becoming corrupted, or is the data being read off > the block device corrupted? > It seems like data being read off the block device is being corrupted, since if we replace highmem kernel with a non-highmem kernel the filesystem is able to bootup fine.