From: Yifeng Li <tomli@tomli.me>
To: Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
Teddy Wang <teddy.wang@siliconmotion.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org, Yifeng Li <tomli@tomli.me>,
stable@vger.kernel.org
Subject: [PATCH 3/8] fbdev: sm712fb: fix VRAM detection, don't set SR70/71/74/75.
Date: Sun, 17 Mar 2019 06:24:59 +0800 [thread overview]
Message-ID: <20190316222504.27170-4-tomli@tomli.me> (raw)
In-Reply-To: <20190316222504.27170-1-tomli@tomli.me>
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 <tomli@tomli.me>
Cc: stable@vger.kernel.org # v4.4+
---
drivers/video/fbdev/sm712fb.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/video/fbdev/sm712fb.c b/drivers/video/fbdev/sm712fb.c
index a19655babf67..1a3d232c2916 100644
--- a/drivers/video/fbdev/sm712fb.c
+++ b/drivers/video/fbdev/sm712fb.c
@@ -1146,7 +1146,9 @@ static void sm7xx_set_timing(struct smtcfb_info *sfb)
/* init SEQ register SR30 - SR75 */
for (i = 0; i < SIZE_SR30_SR75; i++)
if ((i + 0x30) != 0x30 && (i + 0x30) != 0x62 &&
- (i + 0x30) != 0x6a && (i + 0x30) != 0x6b)
+ (i + 0x30) != 0x6a && (i + 0x30) != 0x6b &&
+ (i + 0x30) != 0x70 && (i + 0x30) != 0x71 &&
+ (i + 0x30) != 0x74 && (i + 0x30) != 0x75)
smtc_seqw(i + 0x30,
vgamode[j].init_sr30_sr75[i]);
--
2.20.1
next prev parent reply other threads:[~2019-03-16 22:32 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190316222504.27170-1-tomli@tomli.me>
2019-03-16 22:24 ` [PATCH 1/8] fbdev: sm712fb: fix white screen of death on reboot, don't set CR3B-CR3F Yifeng Li
2019-03-31 12:18 ` Sudip Mukherjee
2019-03-16 22:24 ` [PATCH 2/8] fbdev: sm712fb: fix brightness control on reboot, don't set SR30 Yifeng Li
2019-03-31 12:19 ` Sudip Mukherjee
2019-03-16 22:24 ` Yifeng Li [this message]
2019-03-31 12:19 ` [PATCH 3/8] fbdev: sm712fb: fix VRAM detection, don't set SR70/71/74/75 Sudip Mukherjee
2019-03-16 22:25 ` [PATCH 4/8] fbdev: sm712fb: fix boot screen glitch when sm712fb replaces VGA Yifeng Li
2019-03-31 12:19 ` Sudip Mukherjee
2019-03-16 22:25 ` [PATCH 5/8] fbdev: sm712fb: fix crashes during framebuffer writes by correctly mapping VRAM Yifeng Li
2019-03-24 21:39 ` Sudip Mukherjee
2019-03-31 12:20 ` Sudip Mukherjee
2019-03-16 22:25 ` [PATCH 6/8] fbdev: sm712fb: fix crashes and garbled display during DPMS modesetting Yifeng Li
2019-03-31 12:20 ` Sudip Mukherjee
2019-03-16 22:25 ` [PATCH 7/8] fbdev: sm712fb: fix support for 1024x768-16 mode Yifeng Li
2019-03-31 12:20 ` Sudip Mukherjee
2019-03-16 22:25 ` [PATCH 8/8] fbdev: sm712fb: use 1024x768 by default on non-MIPS, fix garbled display Yifeng Li
2019-03-31 12:21 ` Sudip Mukherjee
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