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drm/via: attempt again to stabilise the AGP DMA command submission.

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It's worth remembering that all new bright ideas on how to make this command reader work properly and according to docs will probably fail :( Bring in some old code.

Also allow a larger SG-DMA download stride, and remove unnecessary waits for
command regulators pauses.

Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Thomas Hellstrom 2008-03-17 10:07:20 +10:00 committed by Dave Airlie
parent 9df5808cca
commit f0fb6d7798
2 changed files with 54 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

59
drivers/char/drm/via_dma.c
View File

@ -126,6 +126,8 @@ via_cmdbuf_wait(drm_via_private_t * dev_priv, unsigned int size)
hw_addr, cur_addr, next_addr);
return -1;
}
if ((cur_addr < hw_addr) && (next_addr >= hw_addr))
msleep(1);
} while ((cur_addr < hw_addr) && (next_addr >= hw_addr));
return 0;
}
@ -416,27 +418,50 @@ static int via_hook_segment(drm_via_private_t * dev_priv,
int paused, count;
volatile uint32_t *paused_at = dev_priv->last_pause_ptr;
uint32_t reader,ptr;
uint32_t diff;
paused = 0;
via_flush_write_combine();
(void) *(volatile uint32_t *)(via_get_dma(dev_priv) -1);
*paused_at = pause_addr_lo;
via_flush_write_combine();
(void) *paused_at;
reader = *(dev_priv->hw_addr_ptr);
ptr = ((volatile char *)paused_at - dev_priv->dma_ptr) +
dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr + 4;
dev_priv->last_pause_ptr = via_get_dma(dev_priv) - 1;
if ((ptr - reader) <= dev_priv->dma_diff ) {
count = 10000000;
while (!(paused = (VIA_READ(0x41c) & 0x80000000)) && count--);
/*
* If there is a possibility that the command reader will
* miss the new pause address and pause on the old one,
* In that case we need to program the new start address
* using PCI.
*/
diff = (uint32_t) (ptr - reader) - dev_priv->dma_diff;
count = 10000000;
while(diff == 0 && count--) {
paused = (VIA_READ(0x41c) & 0x80000000);
if (paused)
break;
reader = *(dev_priv->hw_addr_ptr);
diff = (uint32_t) (ptr - reader) - dev_priv->dma_diff;
}
paused = VIA_READ(0x41c) & 0x80000000;
if (paused && !no_pci_fire) {
reader = *(dev_priv->hw_addr_ptr);
if ((ptr - reader) == dev_priv->dma_diff) {
diff = (uint32_t) (ptr - reader) - dev_priv->dma_diff;
diff &= (dev_priv->dma_high - 1);
if (diff != 0 && diff < (dev_priv->dma_high >> 1)) {
DRM_ERROR("Paused at incorrect address. "
"0x%08x, 0x%08x 0x%08x\n",
ptr, reader, dev_priv->dma_diff);
} else if (diff == 0) {
/*
* There is a concern that these writes may stall the PCI bus
* if the GPU is not idle. However, idling the GPU first
@ -577,6 +602,7 @@ static void via_cmdbuf_jump(drm_via_private_t * dev_priv)
uint32_t pause_addr_lo, pause_addr_hi;
uint32_t jump_addr_lo, jump_addr_hi;
volatile uint32_t *last_pause_ptr;
uint32_t dma_low_save1, dma_low_save2;
agp_base = dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr;
via_align_cmd(dev_priv, HC_HAGPBpID_JUMP, 0, &jump_addr_hi,
@ -603,8 +629,29 @@ static void via_cmdbuf_jump(drm_via_private_t * dev_priv)
&pause_addr_lo, 0);
*last_pause_ptr = pause_addr_lo;
dma_low_save1 = dev_priv->dma_low;
via_hook_segment( dev_priv, jump_addr_hi, jump_addr_lo, 0);
/*
* Now, set a trap that will pause the regulator if it tries to rerun the old
* command buffer. (Which may happen if via_hook_segment detecs a command regulator pause
* and reissues the jump command over PCI, while the regulator has already taken the jump
* and actually paused at the current buffer end).
* There appears to be no other way to detect this condition, since the hw_addr_pointer
* does not seem to get updated immediately when a jump occurs.
*/
last_pause_ptr =
via_align_cmd(dev_priv, HC_HAGPBpID_PAUSE, 0, &pause_addr_hi,
&pause_addr_lo, 0) - 1;
via_align_cmd(dev_priv, HC_HAGPBpID_PAUSE, 0, &pause_addr_hi,
&pause_addr_lo, 0);
*last_pause_ptr = pause_addr_lo;
dma_low_save2 = dev_priv->dma_low;
dev_priv->dma_low = dma_low_save1;
via_hook_segment(dev_priv, jump_addr_hi, jump_addr_lo, 0);
dev_priv->dma_low = dma_low_save2;
via_hook_segment(dev_priv, pause_addr_hi, pause_addr_lo, 0);
}

2
drivers/char/drm/via_dmablit.c
View File

@ -603,7 +603,7 @@ via_build_sg_info(struct drm_device *dev, drm_via_sg_info_t *vsg, drm_via_dmabli
* (Not a big limitation anyway.)
*/
if ((xfer->mem_stride - xfer->line_length) >= PAGE_SIZE) {
if ((xfer->mem_stride - xfer->line_length) > 2*PAGE_SIZE) {
DRM_ERROR("Too large system memory stride. Stride: %d, "
"Length: %d\n", xfer->mem_stride, xfer->line_length);
return -EINVAL;