From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sudip Mukherjee Date: Sun, 31 Mar 2019 12:19:24 +0000 Subject: Re: [PATCH 3/8] fbdev: sm712fb: fix VRAM detection, don't set SR70/71/74/75. Message-Id: <20190331121924.5wjhhjp2j2gom7zp@debian> List-Id: References: <20190316222504.27170-1-tomli@tomli.me> <20190316222504.27170-4-tomli@tomli.me> In-Reply-To: <20190316222504.27170-4-tomli@tomli.me> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Yifeng Li Cc: Teddy Wang , Bartlomiej Zolnierkiewicz , linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org On Sun, Mar 17, 2019 at 06:24:59AM +0800, Yifeng Li wrote: > On a Thinkpad s30 (Pentium III / i440MX, Lynx3DM), the amount of Video > RAM is not detected correctly by the xf86-video-siliconmotion driver. > This is because sm712fb overwrites the GPR71 Scratch Pad Register, which > is set by BIOS on x86 and used to indicate amount of VRAM. > > Other Scratch Pad Registers, including GPR70/74/75, don't have the same > side-effect, but overwriting to them is still questionable, as they are > not related to modesetting. > > Stop writing to SR70/71/74/75 (a.k.a GPR70/71/74/75). > > Signed-off-by: Yifeng Li > Cc: stable@vger.kernel.org # v4.4+ Tested-by: Sudip Mukherjee -- Regards Sudip