diff options
Diffstat (limited to 'gk104-disable-underflow-reporting/gk104-disable-underflow-reporting.txt')
| -rw-r--r-- | gk104-disable-underflow-reporting/gk104-disable-underflow-reporting.txt | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/gk104-disable-underflow-reporting/gk104-disable-underflow-reporting.txt b/gk104-disable-underflow-reporting/gk104-disable-underflow-reporting.txt new file mode 100644 index 0000000..1519c33 --- /dev/null +++ b/gk104-disable-underflow-reporting/gk104-disable-underflow-reporting.txt @@ -0,0 +1,89 @@ +Synopsis: + +How to address an intermittent problem observed on some GK104-based products. + +Description: + +A diagnostic setting was inadvertently left enabled in the production VBIOS +builds on some NVIDIA GK104-based graphics cards. This setting can result in a +red screen being displayed in some rare cases, for example in response to +certain mode-set operations. + +The setting in question is used as part of the product engineering process to +make display engine underflows more easily human-detectable. This is a scenario +in which the bandwidth provided by the GPU's video memory interface, in the +current performance state (at relevant clock frequencies defined by this state), +is insufficient to satisfy the current isochronous streaming requirements of the +display engine. + +The NVIDIA Accelerated Linux Graphics Driver disables this setting when it +initializes the GPU. However, it is NVIDIA's suggestion that independently +developed drivers also disable it. + +Workaround: + +The underflow detection setting can be disabled by means of the per-head +register NV_PDISP_RG_UNDERFLOW(i), accessible via the GPUs' BAR0 (where 'i' is +the head index): + + NV_PDISP_RG_UNDERFLOW(i) (0x00616308 + (i) * 2048) + +Since the affected GPUs implement four heads, four such registers are +available. To disable the underflow detection, the registers need to be +programmed with the value 0. + +Scope: + +The problem described above affects GK104-based products with VBIOS versions +below 80.04.63.00.00. This includes (but may not be limited to) the following +products: + + PCI ID Product Name + ------- ----------------- + 0x11a0 GeForce GTX 680M + 0x11a1 GeForce GTX 670MX + 0x11a2 GeForce GTX 675MX + 0x11a3 GeForce GTX 680MX + 0x11bc Quadro K5000M + 0x11bd Quadro K4000M + 0x11be Quadro K3000M + +Register Description: + +This register is used for detecting underflows and also determines what action +the hw should take when an underflow occurs. + +ENABLE Turns on underflow reporting. Note that this has no effect on the +underflow mode. The underflow mode (what to do when an underflow occurs, REPEAT +or RED, is always active). + +UNDERFLOWED Indicates whether an underflow has occurred. This is a "sticky" bit. +To clear it, software writes a '1' to this bit. UNDERFLOWED is active +only when the above ENABLE bit is set. + +UNDERFLOW_MODE Indicates what to do when an underflow occurs. If REPEAT +is set, then the raster generator will repeat the last pixel, when a new +pixel is not available. If RED is set, the raster generator will display +bright red for any missing pixels. + + 31 24 23 16 15 8 7 0 +.-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-. +| |0 0 0 0 0 0 0| | RG_UNDERFLOW +`-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-' + +#define NV_PDISP_RG_UNDERFLOW(i) (0x00616308+(i)*2048) /* RW-4A */ +#define NV_PDISP_RG_UNDERFLOW__SIZE_1 4 /* */ +#define NV_PDISP_RG_UNDERFLOW_ENABLE 0:0 /* RWIVF */ +#define NV_PDISP_RG_UNDERFLOW_ENABLE_INIT 0x00000000 /* RWI-V */ +#define NV_PDISP_RG_UNDERFLOW_ENABLE_ENABLE 0x00000001 /* RW--V */ +#define NV_PDISP_RG_UNDERFLOW_ENABLE_DISABLE 0x00000000 /* RW--V */ +#define NV_PDISP_RG_UNDERFLOW_UNDERFLOWED 4:4 /* RWIVF */ +#define NV_PDISP_RG_UNDERFLOW_UNDERFLOWED_INIT 0x00000000 /* RWI-V */ +#define NV_PDISP_RG_UNDERFLOW_UNDERFLOWED_CLR 0x00000001 /* -W--V */ +#define NV_PDISP_RG_UNDERFLOW_UNDERFLOWED_YES 0x00000001 /* R---V */ +#define NV_PDISP_RG_UNDERFLOW_UNDERFLOWED_NO 0x00000000 /* R---V */ +#define NV_PDISP_RG_UNDERFLOW_MODE 8:8 /* RWIVF */ +#define NV_PDISP_RG_UNDERFLOW_MODE_INIT 0x00000000 /* RWI-V */ +#define NV_PDISP_RG_UNDERFLOW_MODE_REPEAT 0x00000000 /* RW--V */ +#define NV_PDISP_RG_UNDERFLOW_MODE_RED 0x00000001 /* RW--V */ + |