From: Stephen Boyd Date: Thu, 11 Apr 2013 01:00:11 +0000 (-0700) Subject: ARM: msm: Fix uncompess.h tx underrun check X-Git-Tag: firefly_0821_release~3680^2~608^2~8^2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=73a8c28f167c9e7bc42eafc0bcbd298031709430;p=firefly-linux-kernel-4.4.55.git ARM: msm: Fix uncompess.h tx underrun check Bit 3 of the SR register is set if there is a tx underrun. If this bit isn't set, we should loop on the tx ready bit until we can transmit again. Otherwise we should skip the loop and transmit immediately. The code is doing the opposite though, checking for an underrun and then looping on the tx ready bit causing us to never loop on the tx read bit when the tx buffer may not be ready. This doesn't seem to affect my 8960 device too often, but in some cases I see a lost character or two from the decompressor prints. This also matches what we do in the assembly in debug-macro.S. Signed-off-by: Stephen Boyd Signed-off-by: David Brown --- diff --git a/arch/arm/mach-msm/include/mach/uncompress.h b/arch/arm/mach-msm/include/mach/uncompress.h index fa97a10d8695..94324870fb04 100644 --- a/arch/arm/mach-msm/include/mach/uncompress.h +++ b/arch/arm/mach-msm/include/mach/uncompress.h @@ -37,7 +37,7 @@ static void putc(int c) * Wait for TX_READY to be set; but skip it if we have a * TX underrun. */ - if (UART_DM_SR & 0x08) + if (!(UART_DM_SR & 0x08)) while (!(UART_DM_ISR & 0x80)) cpu_relax();