diff options
authorRussell Currey <ruscur@russell.cc>2016-12-15 16:12:41 +1100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2016-12-18 14:39:50 +0100
commit298360af3dab45659810fdc51aba0c9f4097e4f6 (patch)
parent2cf026ae85c42f253feb9f420d1b4bc99bd5503d (diff)
drivers/gpu/drm/ast: Fix infinite loop if read failsdrm-misc-fixes-2016-12-22
ast_get_dram_info() configures a window in order to access BMC memory. A BMC register can be configured to disallow this, and if so, causes an infinite loop in the ast driver which renders the system unusable. Fix this by erroring out if an error is detected. On powerpc systems with EEH, this leads to the device being fenced and the system continuing to operate. Cc: <stable@vger.kernel.org> # 3.10+ Signed-off-by: Russell Currey <ruscur@russell.cc> Reviewed-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/20161215051241.20815-1-ruscur@russell.cc
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c
index 904beaa932d0..f75c6421db62 100644
--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -223,7 +223,8 @@ static int ast_get_dram_info(struct drm_device *dev)
ast_write32(ast, 0x10000, 0xfc600309);
do {
- ;
+ if (pci_channel_offline(dev->pdev))
+ return -EIO;
} while (ast_read32(ast, 0x10000) != 0x01);
data = ast_read32(ast, 0x10004);
@@ -428,7 +429,9 @@ int ast_driver_load(struct drm_device *dev, unsigned long flags)
ast_detect_chip(dev, &need_post);
if (ast->chip != AST1180) {
- ast_get_dram_info(dev);
+ ret = ast_get_dram_info(dev);
+ if (ret)
+ goto out_free;
ast->vram_size = ast_get_vram_info(dev);
DRM_INFO("dram %d %d %d %08x\n", ast->mclk, ast->dram_type, ast->dram_bus_width, ast->vram_size);

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