https://bugzilla.kernel.org/show_bug.cgi?id=26562

Summary: [bisected] blank screen with radeon.modeset=1 Product: Drivers Version: 2.5 Kernel Version: 2.6.37 Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Video(DRI - non Intel) AssignedTo: drivers_video-dri@kernel-bugs.osdl.org ReportedBy: sliedes@cc.hut.fi CC: airlied@linux.ie, alexdeucher@gmail.com Regression: Yes

Hi,

On 2.6.37, I get blank screen with my RV630 desktop radeon with KMS on (kernel parameter radeon.modeset=1). 2.6.36 works fine. The computer does not crash, the only symptom I can find is no signal to the screen.

I have bisected the problem down to this commit:

------------------------------------------------------------ 48dfaaeb6637240af3089bf9b7a00a6cf24e0182 is the first bad commit commit 48dfaaeb6637240af3089bf9b7a00a6cf24e0182 Author: Alex Deucher alexdeucher@gmail.com Date: Wed Sep 29 11:37:41 2010 -0400

drm/radeon/kms: remove new pll algo

The recent changes to the old algo (prefer high post div) coupled with the range and precision limitations of using fixed point with the new algo make the new algo less useful. So drop the new algo. This should work as well or better than the old new/old combinations and simplifies the code a lot.

Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=30218 among others.

Signed-off-by: Alex Deucher alexdeucher@gmail.com Signed-off-by: Dave Airlie airlied@redhat.com ------------------------------------------------------------

lspci -v:

------------------------------------------------------------ 01:00.0 VGA compatible controller: ATI Technologies Inc RV630 [Radeon HD 2600 Series] (prog-if 00 [VGA controller]) Subsystem: PC Partner Limited Device e410 Flags: bus master, fast devsel, latency 0, IRQ 16 Memory at d0000000 (64-bit, prefetchable) [size=256M] Memory at fe620000 (64-bit, non-prefetchable) [size=64K] I/O ports at e000 [size=256] Expansion ROM at fe600000 [disabled] [size=128K] Capabilities: [50] Power Management version 3 Capabilities: [58] Express Legacy Endpoint, MSI 00 Capabilities: [a0] MSI: Enable- Count=1/1 Maskable- 64bit+ Capabilities: [100] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?>

01:00.1 Audio device: ATI Technologies Inc RV630/M76 audio device [Radeon HD 2600 Series] Subsystem: PC Partner Limited Device aa08 Flags: bus master, fast devsel, latency 0, IRQ 67 Memory at fe630000 (64-bit, non-prefetchable) [size=16K] Capabilities: [50] Power Management version 3 Capabilities: [58] Express Legacy Endpoint, MSI 00 Capabilities: [a0] MSI: Enable+ Count=1/1 Maskable- 64bit+ Capabilities: [100] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?> Kernel driver in use: HDA Intel ------------------------------------------------------------

I tried to diagnose this further with `radeontool regs', but there is no difference in the output between the last good commit (f28488c2) with screen in the working state and the first bad commit (48dfaaeb) with the screen blanked. Here's its output with a text console on the screen (no X):

------------------------------------------------------------ RADEON_DAC_CNTL 00000000 RADEON_DAC_EXT_CNTL 00000000 RADEON_DAC_MACRO_CNTL 00000000 RADEON_DAC_CNTL2 00000000 RADEON_TV_DAC_CNTL 00000000 RADEON_DISP_OUTPUT_CNTL 00000000 RADEON_CONFIG_MEMSIZE 00000000 RADEON_AUX_SC_CNTL 2ba7a25e RADEON_CRTC_EXT_CNTL 00000000 RADEON_CRTC_GEN_CNTL 00000000 RADEON_CRTC2_GEN_CNTL 00000000 RADEON_DEVICE_ID 00000000 RADEON_DISP_MISC_CNTL 00000000 RADEON_GPIO_MONID 00000000 RADEON_GPIO_MONIDB 00000000 RADEON_GPIO_CRT2_DDC 00000000 RADEON_GPIO_DVI_DDC 00000000 RADEON_GPIO_VGA_DDC 00000000 RADEON_LVDS_GEN_CNTL 00000000 RADEON_LVDS_PLL_CNTL 00000000 RADEON_FP_GEN_CNTL 00000000 RADEON_FP2_GEN_CNTL 00000000 RADEON_PPLL_CNTL 00000000 RADEON_PPLL_REF_DIV 00000000 RADEON_PPLL_DIV_3 00000000 RADEON_PIXCLKS_CNTL 00000000 RADEON_P2PLL_CNTL 00000000 RADEON_P2PLL_REF_DIV 00000000 RADEON_P2PLL_DIV_0 00000000 RADEON_VCLK_ECP_CNTL 00000000 RADEON_MEM_TIMING_CNTL 00000000 RADEON_TMDS_PLL_CNTL 00000000 RADEON_TMDS_TRANSMITTER_CNTL 00000000 RADEON_CRTC_MORE_CNTL 00000000 RADEON_FP_H_SYNC_STRT_WID 00000000 RADEON_FP_V_SYNC_STRT_WID 00000000 RADEON_FP_CRTC_H_TOTAL_DISP 00000000 RADEON_FP_CRTC_V_TOTAL_DISP 00000000 RADEON_FP_HORZ_STRETCH 00000000 RADEON_FP_VERT_STRETCH 00000000 RADEON_FP_HORZ_VERT_ACTIVE 00000000 RADEON_CRTC_H_TOTAL_DISP 00000000 RADEON_CRTC_H_SYNC_STRT_WID 00000000 RADEON_CRTC_V_TOTAL_DISP 00000000 RADEON_CRTC_V_SYNC_STRT_WID 00000000 RADEON_CRTC2_H_TOTAL_DISP 0200000f RADEON_CRTC2_H_SYNC_STRT_WID 00000000 RADEON_CRTC2_V_TOTAL_DISP 00000100 RADEON_CRTC2_V_SYNC_STRT_WID 00000002 ------------------------------------------------------------

If there's anything further you need me to do to diagnose this, I'll be happy to help.

--- Comment #1 from Sami Liedes sliedes@cc.hut.fi 2011-01-12 13:30:45 --- Did the mail for this bug go anywhere?? Bugzilla timed out and I certainly did not get any mail about this (I should per my bugzilla preferences), but the bug has been created.