From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Date: Sun, 5 Aug 2018 14:47:09 +0200 Subject: [Buildroot] [PATCH 1/2] qemu/sh4-r2d: restore the old sh-sci driver behaviour In-Reply-To: <20180616112532.26275-1-romain.naour@gmail.com> References: <20180616112532.26275-1-romain.naour@gmail.com> Message-ID: <20180805144709.2b2b319e@windsurf> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Hello, On Sat, 16 Jun 2018 13:25:31 +0200, Romain Naour wrote: > This reverts commit 18e8cf159177100e69d528293f8cf6875c0b1bca (kernel) > > The last Qemu kernel update [1] introduced a regresion in sh4 SCIF > serial device. Some keyboard presses are very slow to be taken into > account, perhaps not even taken into account at all. This would > explain why our test infrastructure doesn?t manage to login as root > [2][3][4]. > > git bisect reported a kernel patch from 4.11, increasing RX FIFO > trigger defaults value for sh-sci (H)SCIF. The kernel patch itself > looks good but the Qemu emulation is not ready to handle this new > setting. > > From Qemu (2.12.0): target/sh4/README.sh4 > "Configuration of the second serial port (SCIF) is supported. FIFO > handling infrastructure has been started but is not completed yet." > > We can't use the first serial port (ttySC0) because it's the second > SH UART that's emulated by Qemu. > > In order to be able to test sh4 architecture with newer kernel, > revert to the old behaviour. > > [1] 03fb00f2175cdb4565e26fcb9b3da1c1059de1bd > [2] https://gitlab.com/free-electrons/toolchains-builder/-/jobs/72006425 > [3] https://gitlab.com/free-electrons/toolchains-builder/-/jobs/72006427 > [4] https://gitlab.com/free-electrons/toolchains-builder/-/jobs/72006426 > > Signed-off-by: Romain Naour > Cc: Thomas Petazzoni > --- > ...al-sh-sci-increase-RX-FIFO-trigger-defaul.patch | 61 ++++++++++++++++++++++ > configs/qemu_sh4_r2d_defconfig | 1 + > 2 files changed, 62 insertions(+) > create mode 100644 board/qemu/sh4-r2d/patches/linux/0001-Revert-serial-sh-sci-increase-RX-FIFO-trigger-defaul.patch Both applied to master. Has the issue been reported to upstream Qemu ? Thanks! Thomas -- Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com