On Wed, 13 Jan 2021, Daniël Mantione wrote:

Hi,

If I remember well, the removed lines have to do with the VGA/accelerator
mode of the chip. The current driver always runs the chip in accelerator
mode. Suppose you would want to support high resolution hardware text modes
with the driver (fbdev bpp=0), then you would need to switch the chip into
VGA mode mode and then the removed lines become relevant.

I did some experiments with this when I was working on the driver, but
because the documentation was silent about the behaviour of extended CRTC
registers in VGA mode, I failed to make hardware text modes to work
properly.

The #if 0 was there so code was already there in case me or someone else
would pick it up again.

This code has been commented out for *at least* 16 years.

Probably time to let it go. :)

Best regards,

Daniël Mantione

Op Wed, 13 Jan 2021, schreef Lee Jones:

quoted

Fixes the following W=1 kernel build warning(s):

drivers/video/fbdev/aty/mach64_ct.c: In function ‘aty_init_pll_ct’:
drivers/video/fbdev/aty/mach64_ct.c:405:46: warning: variable ‘vga_dsp_on_off’ set but not used [-Wunused-but-set-variable]
drivers/video/fbdev/aty/mach64_ct.c:405:30: warning: variable ‘vga_dsp_config’ set but not used [-Wunused-but-set-variable]
drivers/video/fbdev/aty/mach64_ct.c:405:18: warning: variable ‘dsp_on_off’ set but not used [-Wunused-but-set-variable]

Cc: daniel.mantione@freepascal.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Signed-off-by: Lee Jones <redacted>
---
drivers/video/fbdev/aty/mach64_ct.c | 19 ++-----------------
1 file changed, 2 insertions(+), 17 deletions(-)

diff --git a/drivers/video/fbdev/aty/mach64_ct.c b/drivers/video/fbdev/aty/mach64_ct.c
index f87cc81f4fa2b..23eececa1e9d7 100644
--- a/drivers/video/fbdev/aty/mach64_ct.c
+++ b/drivers/video/fbdev/aty/mach64_ct.c

@@ -402,7 +402,7 @@ static int aty_init_pll_ct(const struct fb_info *info, union aty_pll *pll)

	struct atyfb_par *par = (struct atyfb_par *) info->par;
	u8 mpost_div, xpost_div, sclk_post_div_real;
	u32 q, memcntl, trp;
-	u32 dsp_config, dsp_on_off, vga_dsp_config, vga_dsp_on_off;
+	u32 dsp_config;
#ifdef DEBUG
	int pllmclk, pllsclk;
#endif

@@ -488,25 +488,10 @@ static int aty_init_pll_ct(const struct fb_info *info, union aty_pll *pll)

	/* Allow BIOS to override */
	dsp_config = aty_ld_le32(DSP_CONFIG, par);
-	dsp_on_off = aty_ld_le32(DSP_ON_OFF, par);
-	vga_dsp_config = aty_ld_le32(VGA_DSP_CONFIG, par);
-	vga_dsp_on_off = aty_ld_le32(VGA_DSP_ON_OFF, par);

	if (dsp_config)
		pll->ct.dsp_loop_latency = (dsp_config & DSP_LOOP_LATENCY) >> 16;
-#if 0
-	FIXME: is it relevant for us?
-	if ((!dsp_on_off && !M64_HAS(RESET_3D)) ||
-		((dsp_on_off == vga_dsp_on_off) &&
-		(!dsp_config || !((dsp_config ^ vga_dsp_config) & DSP_XCLKS_PER_QW)))) {
-		vga_dsp_on_off &= VGA_DSP_OFF;
-		vga_dsp_config &= VGA_DSP_XCLKS_PER_QW;
-		if (ATIDivide(vga_dsp_on_off, vga_dsp_config, 5, 1) > 24)
-			pll->ct.fifo_size = 32;
-		else
-			pll->ct.fifo_size = 24;
-	}
-#endif
+
	/* Exit if the user does not want us to tamper with the clock
	rates of her chip. */
	if (par->mclk_per == 0) {

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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