From mboxrd@z Thu Jan 1 00:00:00 1970 From: rmallon@gmail.com (Ryan Mallon) Date: Sun, 17 Mar 2013 11:06:29 +1100 Subject: ep93xx irq-vic regression In-Reply-To: <201303161449.03823.florian@openwrt.org> References: <5143AAB4.6020406@gmail.com> <201303161449.03823.florian@openwrt.org> Message-ID: <51450905.8030108@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 17/03/13 00:49, Florian Fainelli wrote: > Hello, > > Le samedi 16 mars 2013 01:16:52, H Hartley Sweeten a ?crit : > [snip] > >> >> ARM: ep93xx: properly wait for UART FIFO to be empty >> >> Reverting that one allows my system to boot with 3.9.0-rc2. >> >> Instead of removing the wait loop completely I propose this >> patch instead. I can repost this patch in a new thread if >> necessary. >> >> Regards, >> Hartley >> >> --- >> >> From: H Hartley Sweeten >> Subject: [PATCH] arm: ep93xx: fix wait for UART FIFO to be empty >> >> commit 210dce5f "ARM: ep93xx: properly wait for UART FIFO to be empty" >> >> Removed the timeout loop while waiting for the uart transmit fifo to >> empty. Some bootloaders leave the uart in a state where there might >> be bytes in the uart that are not transmitted when execution is handed >> over to the kernel. This results in a deadlocked system while waiting >> for the fifo to empty. >> >> Add back the timeout wait to prevent the deadlock. >> >> Increase the wait time to hopefully prevent the decompressor corruption >> that lead to commit 210dce5f. This corruption was probably due to a >> slow uart baudrate. The 10* increase in the wait time should be enough >> for all cases. > > Ok, your solution seems like it would work, when I come accross this bug I > initially ended up doing the same thing and incrementing the number of > iterations in the loop. I was not quite happy with that as it would still be > highly depending on the clocking. Anyway, sorry for breaking your system with > this commit. Do you want to add an Acked/Reviewed-by Florian? I'll queue this up in my tree if you are happy with it. ~Ryan