CC BenH
On Thu, Mar 19, 2015 at 1:30 PM, Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
> Hello FB devs,
>
> This ancient code from 1da177e4c3f4: "Linux-2.6.12-rc2" from Apr 16,
> 2005, leads to the following static checker warning:
Nah, it's a little bit older (in full-history-linux ;-)
commit 9ff343f3d155aa35f79bae8607d7c4500d7ef848
Author: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Date: Thu Feb 10 16:03:30 2005 -0800
[PATCH] radeonfb update
>
> drivers/video/fbdev/aty/radeon_pm.c:417 radeon_pm_enable_dynamic_mode()
> warn: we tested 'tmp & (1 << 21)' before and it was 'true'
>
> include/video/radeon.h
> 1216 #define MCLK_CNTL__MRDCKA1_SOUTSEL_MASK 0x0c000000L
> 1217 #define MCLK_CNTL__MRDCKB0_SOUTSEL_MASK 0x30000000L
> 1218 #define MCLK_CNTL__MRDCKB1_SOUTSEL_MASK 0xc0000000L
> 1219 #define MCLK_CNTL__R300_DISABLE_MC_MCLKA (1 << 21)
> 1220 #define MCLK_CNTL__R300_DISABLE_MC_MCLKB (1 << 21)
>
> These are probably supposed to refer to different bits.
>
> 1221
> 1222 // MCLK_MISC
>
> drivers/video/fbdev/aty/radeon_pm.c
> 411 /* Some releases of vbios have set DISABLE_MC_MCLKA
> 412 * and DISABLE_MC_MCLKB bits in the vbios table. Setting these
> 413 * bits will cause H/W hang when reading video memory with dynamic
> 414 * clocking enabled.
> 415 */
> 416 if ((tmp & MCLK_CNTL__R300_DISABLE_MC_MCLKA) &&
> 417 (tmp & MCLK_CNTL__R300_DISABLE_MC_MCLKB)) {
>
> The duplicate check here causes a warning. I guess it probably doesn't
> matter if no one complains...
>
> 418 /* If both bits are set, then check the active channels */
> 419 tmp = INPLL(pllMCLK_CNTL);
> 420 if (rinfo->vram_width == 64) {
> 421 if (INREG(MEM_CNTL) & R300_MEM_USE_CD_CH_ONLY)
> 422 tmp &= ~MCLK_CNTL__R300_DISABLE_MC_MCLKB;
> 423 else
> 424 tmp &= ~MCLK_CNTL__R300_DISABLE_MC_MCLKA;
> 425 } else {
> 426 tmp &= ~(MCLK_CNTL__R300_DISABLE_MC_MCLKA |
> 427 MCLK_CNTL__R300_DISABLE_MC_MCLKB);
> 428 }
> 429 }
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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