From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Jernej =?utf-8?B?xaBrcmFiZWM=?= To: =?utf-8?B?T25kxZllag==?= Jirman Cc: maxime.ripard@free-electrons.com, wens@csie.org, airlied@linux.ie, robh+dt@kernel.org, mark.rutland@arm.com, mturquette@baylibre.com, sboyd@kernel.org, dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org, linux-sunxi@googlegroups.com Subject: Re: [linux-sunxi] [PATCH v3 06/16] drm/sun4i: Release exclusive clock lock when disabling TCON Date: Fri, 09 Mar 2018 07:19:33 +0100 Message-ID: <2311763.nDsHW3lYFU@jernej-laptop> In-Reply-To: <20180309004455.5s2ohse4jpwinre5@core.my.home> References: <20180301213442.16677-1-jernej.skrabec@siol.net> <20180309001314.bu3zcv5gyqsc52fx@core.my.home> <20180309004455.5s2ohse4jpwinre5@core.my.home> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" List-ID: Hi, Dne petek, 09. marec 2018 ob 01:44:55 CET je Ond=C5=99ej Jirman napisal(a): > Hi, >=20 > I've debugged this further and it seems that the code has incorrect > assumptions. See docs for mode_set_nofb. >=20 > https://elixir.bootlin.com/linux/v4.16-rc4/source/include/drm/drm_modeset= _he > lper_vtables.h#L209 > Does this happen with https://github.com/jernejsk/linux-1/tree/h3_hdmi_v3 ? I also tested running X, but I don't remember having the issue. =20 > I've added traces to a few functions that call clk_.*exclusive.*() > functions, and I see this after a few restarts of Xorg server: >=20 > [ 0.783842] *** sun4i_tcon1_mode_set() > [ 0.783886] *** sun4i_tcon_channel_set_status(..., 1, true) > [ 6.881690] *** sun4i_tcon_channel_set_status(..., 1, false) > [ 6.881758] *** sun4i_tcon_channel_set_status(..., 1, true) > [ 52.335085] *** sun4i_tcon_channel_set_status(..., 1, false) > [ 52.335343] *** sun4i_tcon_channel_set_status(..., 1, true) > [ 68.921079] *** sun4i_tcon_channel_set_status(..., 1, false) > [ 68.921337] *** sun4i_tcon_channel_set_status(..., 1, true) >=20 > mode_set_nofb is called just once, yet sun4i_tcon_channel_set_status(...,= 1, > false) is called multiple times, which leads to unbalanced calls to > clk_set_rate_exclusive and clk_rate_exclusive_put. >=20 > I don't know how to fix this. Since there is no function to check if clock is protected, flag can be=20 introduced within TCON which is set when clock rate is protected and unset= =20 when it is unprotected. That way we could track if clk_rate_exclusive_put()= =20 needs to be called or not. Best regards, Jernej >=20 > regards, > o. >=20 > On Fri, Mar 09, 2018 at 01:13:14AM +0100, 'Ond=C5=99ej Jirman' via linux-= sunxi=20 wrote: > > Hi Jernej, > >=20 > > On Thu, Mar 08, 2018 at 11:57:40PM +0100, Jernej =C5=A0krabec wrote: > > > Hi, > > >=20 > > > Dne =C4=8Detrtek, 08. marec 2018 ob 23:47:17 CET je Ond=C5=99ej Jirma= n napisal(a): > > > > Hi, > > > >=20 > > > > On Thu, Mar 01, 2018 at 10:34:32PM +0100, Jernej Skrabec wrote: > > > > > Currently exclusive TCON clock lock is never released, which, for > > > > > example, prevents changing resolution on HDMI. > > > > >=20 > > > > > In order to fix that, release clock when disabling TCON. TCON is > > > > > always > > > > > disabled first before new mode is set. > > > > >=20 > > > > > Signed-off-by: Jernej Skrabec > > > > > --- > > > > >=20 > > > > > drivers/gpu/drm/sun4i/sun4i_tcon.c | 6 ++++-- > > > > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > >=20 > > > > > diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c > > > > > b/drivers/gpu/drm/sun4i/sun4i_tcon.c index > > > > > 1d714c06ec9d..7f6c4125c89f > > > > > 100644 > > > > > --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c > > > > > +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c > > > > > @@ -102,10 +102,12 @@ static void > > > > > sun4i_tcon_channel_set_status(struct > > > > > sun4i_tcon *tcon, int channel,> > > > > >=20 > > > > > return; > > > > > =09 > > > > > } > > > > >=20 > > > > > - if (enabled) > > > > > + if (enabled) { > > > > >=20 > > > > > clk_prepare_enable(clk); > > > > >=20 > > > > > - else > > > > > + } else { > > > > > + clk_rate_exclusive_put(clk); > > > > >=20 > > > > > clk_disable_unprepare(clk); > > > > >=20 > > > > > + } > > > > >=20 > > > > > } > > > >=20 > > > > At least in the linux-next/master I can't see clk_rate_exclusive_ge= t=20 call: > > > It is in drm-misc/drm-misc-fixes: > > > https://cgit.freedesktop.org/drm/drm-misc/commit/?h=3Ddrm-misc-fixes&= id=3D79 > > > d103a565d16b1893d990b2ee5e0fe71767759f > > >=20 > > > My patch is also applied in same branch, so there should be no issues > > > while > > > merging all those branches. > > >=20 > > > linux-next doesn't have either patches currently: > > > https://git.kernel.org/pub/ > > > scm/linux/kernel/git/next/linux-next.git/log/drivers/gpu/drm/sun4i > > >=20 > > > This is issue only if you manually apply one patch without the other. > >=20 > > I have (and had) both patches applied. There's perhaps some code path, > > where sun4i_tcon_channel_set_status(..., false) is called in unbalanced > > way with regards to clk_set_rate_exclusive(). > >=20 > > The issue occurs when starting Xorg. But Xorg works fine. > >=20 > > regards, > >=20 > > o. > > =20 > > > Best regards, > > > Jernej > > >=20 > > > > $ git grep 'exclusive' linux-next/master -- drivers/gpu/drm/sun4i > > > >=20 > > > > linux-next/master:sun4i_hdmi.h: * On sun5i the threshold is > > > > exclusive, > > > > i.e. does not include, linux-next/master:sun4i_tcon.c: > > > > clk_rate_exclusive_put(clk); linux-next/master:sun4i_tcon.c: > > > > clk_set_rate_exclusive(tcon->dclk, mode->crtc_clock * 1000); > > > > linux-next/master:sun4i_tcon.c: clk_set_rate_exclusive(tcon->sclk= 1, > > > > mode->crtc_clock * 1000); > > > >=20 > > > > and the kernel complains too: > > > >=20 > > > > [ 841.915161] ------------[ cut here ]------------ > > > > [ 841.915187] WARNING: CPU: 0 PID: 273 at > > > > /workspace/megous.com/orangepi-pc/linux-4.16/drivers/clk/clk.c:608 > > > > clk_rate_exclusive_put+0x48/0x4c [ 841.915194] CPU: 0 PID: 273 Com= m: > > > > Xorg > > > > Not tainted 4.16.0-rc4-00268-gbac2ecf73ed0 #13 [ 841.915196] Hardw= are > > > > name: Allwinner sun8i Family > > > > [ 841.915217] [] (unwind_backtrace) from [] > > > > (show_stack+0x10/0x14) [ 841.915228] [] (show_stack) from > > > > [] (dump_stack+0x88/0x9c) [ 841.915237] [] > > > > (dump_stack) from [] (__warn+0xd4/0xf0) [ 841.915244] > > > > [] (__warn) from [] (warn_slowpath_null+0x40/0x= 48) > > > > [ > > > > 841.915250] [] (warn_slowpath_null) from [] > > > > (clk_rate_exclusive_put+0x48/0x4c) [ 841.915261] [] > > > > (clk_rate_exclusive_put) from [] > > > > (sun4i_tcon_set_status+0x178/0x2f0) [ 841.915269] [] > > > > (sun4i_tcon_set_status) from [] > > > > (sun4i_crtc_atomic_disable+0x7c/0xe4) [ 841.915279] [] > > > > (sun4i_crtc_atomic_disable) from [] > > > > (drm_atomic_helper_commit_modeset_disables+0x390/0x46c) [ 841.9152= 88] > > > > [] (drm_atomic_helper_commit_modeset_disables) from > > > > [] > > > > (drm_atomic_helper_commit_tail_rpm+0x18/0x64) [ 841.915295] > > > > [] > > > > (drm_atomic_helper_commit_tail_rpm) from [] > > > > (commit_tail+0x40/0x6c) [ 841.915302] [] (commit_tail) f= rom > > > > [] (drm_atomic_helper_commit+0xbc/0x128) [ 841.915311] > > > > [] (drm_atomic_helper_commit) from [] > > > > (restore_fbdev_mode_atomic+0x100/0x1fc) [ 841.915319] [] > > > > (restore_fbdev_mode_atomic) from [] > > > > (drm_fb_helper_dpms+0x50/0x130) [ 841.915328] [] > > > > (drm_fb_helper_dpms) from [] (drm_fb_helper_blank+0x54/0x= 90) > > > > [ > > > > 841.915337] [] (drm_fb_helper_blank) from [] > > > > (fb_blank+0x54/0xa8) [ 841.915343] [] (fb_blank) from > > > > [] (do_fb_ioctl+0x360/0x62c) [ 841.915351] [] > > > > (do_fb_ioctl) from [] (do_vfs_ioctl+0x9c/0x774) [=20 > > > > 841.915358] > > > > [] (do_vfs_ioctl) from [] (SyS_ioctl+0x34/0x58)= [ > > > > 841.915364] [] (SyS_ioctl) from [] > > > > (ret_fast_syscall+0x0/0x4c) [ 841.915368] Exception stack(0xe5fc5f= a8 > > > > to > > > > 0xe5fc5ff0) > > > > [ 841.915373] 5fa0: 00674f10 00675460 0000000b > > > > 00004611 > > > > 00000001 00000000 [ 841.915379] 5fc0: 00674f10 00675460 00000001 > > > > 00000036 > > > > 00650474 00000000 006504a4 00675df8 [ 841.915382] 5fe0: b61a502c > > > > be8acb2c > > > > b6192c38 b6b152ec > > > > [ 841.915386] ---[ end trace fa81b956197707f8 ]--- > > > >=20 > > > > It looks like clk_rate_exclusive_put inside > > > > sun4i_tcon_channel_set_status is called without first calling some > > > > function that would call > > > > clk_set_rate_exclusive, leading to unbalanced get/put calls. > > > >=20 > > > > regards, > > > >=20 > > > > o. > > > > =20 > > > > > static void sun4i_tcon_lvds_set_status(struct sun4i_tcon *tcon, > > > > >=20 > > > > > -- > > > > > 2.16.2 > > > > >=20 > > > > > -- > > > > > You received this message because you are subscribed to the Google > > > > > Groups > > > > > "linux-sunxi" group. To unsubscribe from this group and stop > > > > > receiving > > > > > emails from it, send an email to > > > > > linux-sunxi+unsubscribe@googlegroups.com. For more options, visit > > > > > https://groups.google.com/d/optout. > > >=20 > > > -- > > > You received this message because you are subscribed to the Google > > > Groups "linux-sunxi" group. To unsubscribe from this group and stop > > > receiving emails from it, send an email to > > > linux-sunxi+unsubscribe@googlegroups.com. For more options, visit > > > https://groups.google.com/d/optout. > >=20 > > -- > > You received this message because you are subscribed to the Google Grou= ps > > "linux-sunxi" group. To unsubscribe from this group and stop receiving > > emails from it, send an email to > > linux-sunxi+unsubscribe@googlegroups.com. For more options, visit > > https://groups.google.com/d/optout.