Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755065Ab1DBHCj (ORCPT ); Sat, 2 Apr 2011 03:02:39 -0400 Received: from vms173009pub.verizon.net ([206.46.173.9]:59186 "EHLO vms173009pub.verizon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752815Ab1DBHCA (ORCPT ); Sat, 2 Apr 2011 03:02:00 -0400 From: Len Brown To: linux-pm@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org, Len Brown , x86@kernel.org Subject: [PATCH 14/18] 2.6.40: x86 idle floppy: remove deprecated disable_hlt()/enable_hlt() Date: Sat, 02 Apr 2011 02:22:56 -0400 Message-id: X-Mailer: git-send-email 1.7.5.rc0 In-reply-to: <1301725380-10579-1-git-send-email-lenb@kernel.org> References: <1301725380-10579-1-git-send-email-lenb@kernel.org> In-reply-to: References: X-Patchwork-Hint: ignore Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5098 Lines: 190 From: Len Brown The X86_32-only disable_hlt/enable_hlt mechanism was used by the 32-bit floppy driver. Its effect was to replace the use of the HLT instruction inside default_idle() with cpu_relax(). This workaround was commented: "disable hlt during certain critical i/o operations" "This halt magic was a workaround for ancient floppy DMA wreckage. It should be safe to remove." Remove the workaround to simplify the idle loop. cc: x86@kernel.org Signed-off-by: Len Brown --- Documentation/feature-removal-schedule.txt | 8 ------ arch/x86/include/asm/system.h | 7 ----- arch/x86/kernel/process.c | 24 ------------------ drivers/block/floppy.c | 36 ---------------------------- 4 files changed, 0 insertions(+), 75 deletions(-) diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 720e698..e1e9bf8 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -6,14 +6,6 @@ be removed from this file. --------------------------- -What: x86 floppy disable_hlt -When: 2.6.40 -Why: ancient workaround of dubious utility clutters the - code used by everybody else. -Who: Len Brown - ---------------------------- - What: CONFIG_APM_CPU_IDLE, and its ability to call APM BIOS in idle When: 2.6.40 Why: This optional sub-feature of APM is of dubious reliability, diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h index 33ecc3e..013dd42 100644 --- a/arch/x86/include/asm/system.h +++ b/arch/x86/include/asm/system.h @@ -93,10 +93,6 @@ do { \ "memory"); \ } while (0) -/* - * disable hlt during certain critical i/o operations - */ -#define HAVE_DISABLE_HLT #else #define __SAVE(reg, offset) "movq %%" #reg ",(14-" #offset ")*8(%%rsp)\n\t" #define __RESTORE(reg, offset) "movq (14-" #offset ")*8(%%rsp),%%" #reg "\n\t" @@ -337,9 +333,6 @@ static inline void clflush(volatile void *__p) #define nop() asm volatile ("nop") -void disable_hlt(void); -void enable_hlt(void); - void cpu_idle_wait(void); extern unsigned long arch_align_stack(unsigned long sp); diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index c485629..09bd118 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -344,34 +344,10 @@ void (*pm_idle)(void); EXPORT_SYMBOL(pm_idle); #endif -#ifdef CONFIG_X86_32 -/* - * This halt magic was a workaround for ancient floppy DMA - * wreckage. It should be safe to remove. - */ -static int hlt_counter; -void disable_hlt(void) -{ - hlt_counter++; -} -EXPORT_SYMBOL(disable_hlt); - -void enable_hlt(void) -{ - hlt_counter--; -} -EXPORT_SYMBOL(enable_hlt); - -static inline int hlt_use_halt(void) -{ - return !hlt_counter; -} -#else static inline int hlt_use_halt(void) { return 1; } -#endif /* * We use this if we don't have any better diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 41ea03f..9a4e006 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -1032,37 +1032,6 @@ static int fd_wait_for_completion(unsigned long delay, timeout_fn function) return 0; } -static DEFINE_SPINLOCK(floppy_hlt_lock); -static int hlt_disabled; -static void floppy_disable_hlt(void) -{ - unsigned long flags; - - WARN_ONCE(1, "floppy_disable_hlt() scheduled for removal in 2.6.40"); - spin_lock_irqsave(&floppy_hlt_lock, flags); - if (!hlt_disabled) { - hlt_disabled = 1; -#ifdef HAVE_DISABLE_HLT - disable_hlt(); -#endif - } - spin_unlock_irqrestore(&floppy_hlt_lock, flags); -} - -static void floppy_enable_hlt(void) -{ - unsigned long flags; - - spin_lock_irqsave(&floppy_hlt_lock, flags); - if (hlt_disabled) { - hlt_disabled = 0; -#ifdef HAVE_DISABLE_HLT - enable_hlt(); -#endif - } - spin_unlock_irqrestore(&floppy_hlt_lock, flags); -} - static void setup_DMA(void) { unsigned long f; @@ -1107,7 +1076,6 @@ static void setup_DMA(void) fd_enable_dma(); release_dma_lock(f); #endif - floppy_disable_hlt(); } static void show_floppy(void); @@ -1709,7 +1677,6 @@ irqreturn_t floppy_interrupt(int irq, void *dev_id) fd_disable_dma(); release_dma_lock(f); - floppy_enable_hlt(); do_floppy = NULL; if (fdc >= N_FDC || FDCS->address == -1) { /* we don't even know which FDC is the culprit */ @@ -1858,8 +1825,6 @@ static void floppy_shutdown(unsigned long data) show_floppy(); cancel_activity(); - floppy_enable_hlt(); - flags = claim_dma_lock(); fd_disable_dma(); release_dma_lock(flags); @@ -4504,7 +4469,6 @@ static void floppy_release_irq_and_dma(void) #if N_FDC > 1 set_dor(1, ~8, 0); #endif - floppy_enable_hlt(); if (floppy_track_buffer && max_buffer_sectors) { tmpsize = max_buffer_sectors * 1024; -- 1.7.5.rc0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/