Re: [RFC PATCH 0/2] clk: rockchip: leave npll for DCLK_VOP0(HDMI) only
Quoting Heiko Stübner (2015-01-08 14:30:01) > Hi Kever, > > Am Montag, 17. November 2014, 22:55:36 schrieb Kever Yang: > > To support all kinds of frequency requirement for HDMI on rk3288, > > we need a PLL that can change rate at run time. > > > > There are some discussion before at [0], I think we can just leave > > the npll for HDMI(DCLK_VOP0) used to make it simple. > > > > Comments are welcome. > > I think I said it in private somewhere already, but just so it's also > available publically: > > I don't think customizing/limiting the clock usage like this will fly, > especially as this would require each and every rk3288 board to use vop0 for > hdmi and vop1 for other stuff. > > With the new rk3288 Firefly devboard this concern already becomes reality. > There a vga converter is connected to VOP0, which leaves only vop1 for hdmi > if > one wants to support the vga connection. > > > From our discussion about this problem I remember that the missing clock > frequencies only affected more esotheric screen resolutions, so personally > I'm > not this much concerned an would like to wait till we find a better solution > to > the problem. Ack. We shouldn't have to limit the possible hardware configurations in software just to keep things simple. This points to a deficiency in the clock framework. This is a common concern: how to change a clock frequency for one user without exploding all of the other users. Do you think Tomeu's constraints API[0] might be a step in the right direction for you? [0] http://lkml.kernel.org/r/<1421071809-17402-3-git-send-email-tomeu.viz...@collabora.com> Regards, Mike > > > Heiko -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC PATCH 0/2] clk: rockchip: leave npll for DCLK_VOP0(HDMI) only
Quoting Heiko Stübner (2015-01-08 14:30:01) Hi Kever, Am Montag, 17. November 2014, 22:55:36 schrieb Kever Yang: To support all kinds of frequency requirement for HDMI on rk3288, we need a PLL that can change rate at run time. There are some discussion before at [0], I think we can just leave the npll for HDMI(DCLK_VOP0) used to make it simple. Comments are welcome. I think I said it in private somewhere already, but just so it's also available publically: I don't think customizing/limiting the clock usage like this will fly, especially as this would require each and every rk3288 board to use vop0 for hdmi and vop1 for other stuff. With the new rk3288 Firefly devboard this concern already becomes reality. There a vga converter is connected to VOP0, which leaves only vop1 for hdmi if one wants to support the vga connection. From our discussion about this problem I remember that the missing clock frequencies only affected more esotheric screen resolutions, so personally I'm not this much concerned an would like to wait till we find a better solution to the problem. Ack. We shouldn't have to limit the possible hardware configurations in software just to keep things simple. This points to a deficiency in the clock framework. This is a common concern: how to change a clock frequency for one user without exploding all of the other users. Do you think Tomeu's constraints API[0] might be a step in the right direction for you? [0] http://lkml.kernel.org/r/1421071809-17402-3-git-send-email-tomeu.viz...@collabora.com Regards, Mike Heiko -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC PATCH 0/2] clk: rockchip: leave npll for DCLK_VOP0(HDMI) only
Hi Kever, Am Montag, 17. November 2014, 22:55:36 schrieb Kever Yang: > To support all kinds of frequency requirement for HDMI on rk3288, > we need a PLL that can change rate at run time. > > There are some discussion before at [0], I think we can just leave > the npll for HDMI(DCLK_VOP0) used to make it simple. > > Comments are welcome. I think I said it in private somewhere already, but just so it's also available publically: I don't think customizing/limiting the clock usage like this will fly, especially as this would require each and every rk3288 board to use vop0 for hdmi and vop1 for other stuff. With the new rk3288 Firefly devboard this concern already becomes reality. There a vga converter is connected to VOP0, which leaves only vop1 for hdmi if one wants to support the vga connection. >From our discussion about this problem I remember that the missing clock frequencies only affected more esotheric screen resolutions, so personally I'm not this much concerned an would like to wait till we find a better solution to the problem. Heiko -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC PATCH 0/2] clk: rockchip: leave npll for DCLK_VOP0(HDMI) only
Hi Kever, Am Montag, 17. November 2014, 22:55:36 schrieb Kever Yang: To support all kinds of frequency requirement for HDMI on rk3288, we need a PLL that can change rate at run time. There are some discussion before at [0], I think we can just leave the npll for HDMI(DCLK_VOP0) used to make it simple. Comments are welcome. I think I said it in private somewhere already, but just so it's also available publically: I don't think customizing/limiting the clock usage like this will fly, especially as this would require each and every rk3288 board to use vop0 for hdmi and vop1 for other stuff. With the new rk3288 Firefly devboard this concern already becomes reality. There a vga converter is connected to VOP0, which leaves only vop1 for hdmi if one wants to support the vga connection. From our discussion about this problem I remember that the missing clock frequencies only affected more esotheric screen resolutions, so personally I'm not this much concerned an would like to wait till we find a better solution to the problem. Heiko -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
