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a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1709626480; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=QNj7PzdvPD7WI4n6gxvH/sldUw13zTEnUHfCfXtrBfY=; b=AW1ONpUi54JG/W8Xq0iCOJ+eRZYJ71mlsZBTKucUQukQApG9jkJQp/vHbhqXgmx1KJcg0q xrymlFFOn0K0nfGkWctpzzoZ72zAPuBe0YI8psTYXU+GxSCjkbH5vRUKBIIaxxNujxjllB dH1dWuw1wM2cbKyB0MrxCclkRTYo8Dz/mRGbxw2dgMMFL9utPOrct/XyJ7udlpwyoc5YVQ 42WlvyPN2gFl6YCASoEctdlIzZGQICvvsf3e9VpNi7UV0Z2KQbJforFdImyUNpJDlvxkl7 mHKEkbHEflkF1p2+FXc6E0mija2dsyi8/2T0QfXLX+2vQ3g1hwTtRERCBcZ33g== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1709626480; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=QNj7PzdvPD7WI4n6gxvH/sldUw13zTEnUHfCfXtrBfY=; b=U+YKs3J2V6X7uOq6wIPVddHSenSEATkimtwzqfXS5cAp6V6TjivHnzU/TBO8ROHOj9ZFab t0bUT9BLfjBLuECQ== To: Daniel Vetter , DRI Development Cc: LKML , Daniel Vetter , Daniel Vetter , Jocelyn Falempe , Andrew Morton , "Peter Zijlstra (Intel)" , Lukas Wunner , Petr Mladek , Steven Rostedt , Sergey Senozhatsky , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter Subject: Re: [RFC] drm/panic: Add drm panic locking In-Reply-To: <20240301103903.2538083-1-daniel.vetter@ffwll.ch> References: <20240301100516.2516297-1-daniel.vetter@ffwll.ch> <20240301103903.2538083-1-daniel.vetter@ffwll.ch> Date: Tue, 05 Mar 2024 09:20:04 +0106 Message-ID: <87o7bt6qpf.fsf@jogness.linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Hi Daniel, Great to see this moving forward! On 2024-03-01, Daniel Vetter wrote: > But for the initial cut of a drm panic printing support I don't think > we need that, because the critical sections are extremely small and > only happen once per display refresh. So generally just 60 tiny locked > sections per second, which is nothing compared to a serial console > running a 115kbaud doing really slow mmio writes for each byte. So for > now the raw spintrylock in drm panic notifier callback should be good > enough. Is there a reason you do not use the irqsave/irqrestore variants? By leaving interrupts enabled, there is the risk that a panic from any interrupt handler may block the drm panic handler. John Ogness